ElevenSmooth FAQ
Searching for factors of the Mersenne number

M(3326400) = 23326400-1


    Basic Questions

  1. What do you do?
  2. Why do you do it?
  3. When do you do it?
  4. How do you do it?
  5. What does the ECMclient program do?
  6. What are these assignments?
  7. What does the ECM program do?
  8. What do lines like "Received 2_11880P.C853/B1=250000" mean?
  9. The final line begins "1:010" - it keeps changing - what's that mean?
  10. Why doesn't the percentage update in Stage 2 - it always says 2:000?
  11. Project Questions

  12. What does "ElevenSmooth" Mean?
  13. What is the "Special Project"?
  14. How can I work on only record setting factorizations?
  15. How can I remove the ElevenSmooth icon from the ecmclient program?
  16. What changes are planned for the web site?
  17. Math Questions

  18. How many decimal digits are in 23,326,400-1?
  19. Are these factors of any use?
  20. How does the Elliptical Curve Method (ECM) work, practically?
  21. How does the Elliptical Curve Method (ECM) work, theoretically?
  22. What are "Algebraic Factors"?
  23. What are "Primitive Parts"?
  24. How is the Primitive Part calculated when the exponent has only distinct odd prime factors?
  25. Why does this method fail with repeated prime factors?
  26. How is the Primitive Part calculated with repeated factors of the exponent?
  27. What are "Aurifeuillian Factors"?
  28. What is the divisibility rule for Aurifeuillian Factors?
  29. How are Primitive Parts of Aurifeuillian Factors calculated?
  30. How are Aurifeuillian factors used?
  31. What is the Poisson Approximation?
  32. How many factors do we expect a number to have in a size range?
  33. What is the expected (average) size of factors in a range?
  34. What's the probability of finding a factor in one curve?
  35. What's the probability of finding a factor in "N" curves?
  36. What's the probability a number has no factors in a range?
  37. What's the probability a residual cofactor will be prime?
  38. What's the probability that primes in a range will complete a factorization?
  39. What composite numbers are being distributed by the ECM Server?
  40. What's the relationship between ElevenSmooth and the Cunningham Project?
  41. What's the relationship between ElevenSmooth and GIMPS?
  42. Will we find ALL the factors of M(3326400)?
  43. When will we quit?
  44. Why 3326400?
  45. Web Questions

  46. How can I recolor GIFs?
  47. How can I make favicons?
  48. How can I get favicons to display?
  49. How can I make a sortable table like on the Factors Page?
  50. How can I make dynamic cell backgrounds like on the Planner Page?
  51. How do you change the Subject on the Contact Page from different places?
  52. How do you change all the Bottom Links without editing every page?
  53. How can I make screenshot images?
  54. How can I make images of mathematical expressions?
  55. How does the Contact Page send mail?
  56. How did you get the web space for ElevenSmooth?
  57. How did you get the domain name "ElevenSmooth.com" for only $7/year?
  58. How did you get free URL Forwarding?
  59. How can I thank you?
  60. Other

  61. What do you get out of it?

    Basic Questions

  1. What do you do?
  2. We search for previously unknown prime factors of 23,326,400-1.

  3. Why do you do it?
  4. We do it for fun. Every time we find a factor, we've learned something that's never been known before. We make a contribution to a generations long endeavor that is tracked and updated regularly.

  5. When do you do it?
  6. We do it whenever our computers are turned on, running a program at low priority so that it never delays our usual applications, but progresses while the computer is waiting.

  7. How do you do it?
  8. We run the ECMclient program. ECMclient handles the rest.

  9. What does the ECMclient program do?
  10. ECMclient reaches across the internet to get an assignment from the ECM Server. It then runs the ECM program once at low priority to calculate one curve. When the ECM program finishes, the ECMclient program checks to see if the time set in the configuration file has been reached. This time is the set by the line "maxfreq=30"; for a time longer than 30 minutes, increase this value. Until the time is reached, the ECM program runs more curves. After the time has been reached, the ECMclient program reports back to the ECM Server and gets a new assignment. When a factor is found, the ECMclient program reports immediately.

  11. What are these assignments?
  12. Many primitive factors and Aurifeuillian factors (see math questions) are known for 23,326,400-1. An assignment is one of these factors and a level for the ECM program to work at.

  13. What does the ECM program do?
  14. The ECM program looks for factors of its assigned number using the Elliptical Curve Method. Each time the ECM program runs, it computes one curve. Each curve has a chance of finding a factor. The probability of finding factors varies with the size of the factors and with the B1 and B2 parameters. The amount of effort varies the B1 and B2 parameters. See the Math Questions for more information.

  15. What do lines like "Received 2_11880P.C853/B1=250000" mean?
  16. Each composite number has a name that tells about the number. The name of this number is 2_11880P.C853. This name means that the number belongs to the primitive part of 211,880+1, and the number is a composite of 853 digits. The final part means that this assignment is to use ECM curves at the level B1=250000.

  17. The final line begins "1:010" - it keeps changing - what's that mean?
  18. It means the ECM program is 10% complete on Stage 1 of the current curve. The numbers after the colon will increase until they reach 100. During Stage 2 this line always says "2:000" - the display does not change during stage 2. After Stage 2 finishes, another curve will be run unless it's time to contact the ECM Server. The counter will return to 1:000 when Stage 1 of the next curve begins.

  19. Why doesn't the percentage update in Stage 2 - it always says 2:000?
  20. ElevenSmooth uses software written by other people and made freely available on the web. The version of ECM we use doesn't update the percentage during Stage 2, so the ecmclient program cannot update. Source code is available, but there is work ongoing for a new release. I've decided to wait and see if the next release fixes this.


    Project Questions

  21. What does ElevenSmooth Mean?
  22. In number theory, " Smooth" means that a number completely factors into small primes. "11-Smooth" means that no prime factors exceed 11. Examples of 11-smooth numbers are 33, 77, 121, 242, and 231; the largest prime factor for each of these numbers is 11. The largest prime factor of our exponent, 3326400, is 11, so 3326400 is 11-smooth:

    3326400 = 2 6 x 3 3 x 5 2 x 7 x 11

  23. What is the "Special Project"?
  24. The Special Project uses GIMP's program Prime95 to work on all primitives of M(3326400) simultaneously. As a practical matter, this is a search of the 82 primitive factors with exponents that are a multiple of 25 or whose size is over ten thousand digits; the other 63 primitive factors are in the ECM server and have already been searched to higher levels. Prime95 uses Fourier Transforms for its mulitiplications, which makes it much faster on the largest composites. Prime95 works on the full Mersenne number, so the subfactor composites are tested "for free." Hence, as long as any work is planned for the largest composites, it is more efficient to do all the composites using Prime95.

    Stage 1 of the Special Project searched for factors of 15 digits (B1=2K) and found forty new factors. Stage 2, searching for 20 digit factors (B1=11K), found 11 new factors. Stage 3, searching for 25 digit factors (B1=50K), is in process now.

    There are some disadvantages to using Prime95. It requires more attention to download the updated factor files, run the program, and then email the results file. It also tries the patience of some people; at stage 3 each curve takes 15-20 Gigahertz hours. That's not too bad for 82 simultaneous tests, but they don't get the satisfaction of seeing the individual tests rack up. We are considering the tradeoffs for future work in the Special Project.

    The Special Project is currently open to people who have completed at least one full week on the ECM server. Shortly after the completion of one week you should receive an invitation at the email address in your configuration file. If you have been missed, contact me.

  25. How can I work on only record setting factorizations?
  26. Explanations and instructions are on the Download Page.

  27. How can I remove the ElevenSmooth icon from the ecmclient program?
  28. You can download a plain copy of the program or you can remove the icon from your copy. You can download a plain copy directly from Tim Charron's site. You can download the free program Resource Hacker to remove the icon. Resource Hacker will also allow you to change the icon to one of your choosing; that's how I put the ElevenSmooth icon into Tim's program.

  29. What changes are planned for the web site?
  30. Every time I watch somebody new, I find things that need to be explained better and things that I forgot. Fixing these small things has been keeping me pretty busy, but there are some bigger things I work on between these small urgent issues. The things planned right now, in the roughly the order I expect to tackle them, are

    If you think something is missing from this list, tell me about it at the ElevenSmooth Forum or send me a message. Especially if you are volunteering to do it.

    Math Questions

  31. How many decimal digits are in 23,326,400-1?
  32. See MathFAQ

  33. Are these factors of any use?
  34. Prime factors of Mersenne numbers are occasionally useful to mathematicians. For example, NFSNET factored M(713)=2713-1 to help in Richard Brent and Paul Zimmerman's research into primitive trinomials, which have applications in cryptography, coding theory, and random number generation. Factors of Mersenne numbers are also central to the study of covering sets for Sierpinski, Riesel, and Brier numbers. The Cunningham Project has been collecting Mersenne factors (and other factors) since 1925. There is enough interest that Will Edgington updates the file of known factors every few weeks on his web site.

  35. How does the Elliptical Curve Method (ECM) work, practically?
  36. If a number has a 15 digit factor, then each run of the Elliptical Curve Method with B1=2000 has one chance in 25 of finding that factor. Smaller factors will be found with higher probability, larger factors will be found with smaller probabilility. For 20 digit factors we set B1=11000; that gives one chance in ninety of finding a 20 digit factor. We run 25 curves with B1=2000, then 90 curves with B1=11000, then 300 curves with B1=50000, etc. The ECMserver program keeps track of the curves and raises the B1 value when enough curves have been run.

    In reality, the chance of finding a number depends on the B2 value, too. The previous paragraph is correct for the traditional use of B2 = 100 * B1. The newest version of the ECM uses higher values of B2, so it has higher probability of finding a factor. But there isn't yet a new version of the ECMserver.

  37. How does the Elliptical Curve Method (ECM) work, theoretically?
  38. Very few of the people that use ECM understand how it works. The best that most of us can do is to understand Jim Howell's explanation. If you already understand elliptic curve arithmetic, you might understand Paul Zimmerman's description of ECM in The Elliptic Curve Method.

  39. What are "Algebraic Factors"?
  40. If a divides n, then we know from algebra that (xa-1) divides (xn-1) and (xa+1) divides (xn+1). Hence, for every divisor "a" of the exponent "n", we know that (2a-1) is a factor of (2n-1) and that (2a+1) is a factor of (2n+1). The factors (2a-1) and (2a+1) are called Algebraic Factors.

  41. What are "Primitive Parts"?
  42. Because 33 and 77 (and other numbers) divide 231, we know that (233-1) and (277-1) (and other numbers) are algebraic factors of (2231-1). You can remove the contributions of these algebraic factors from (2231-1). When you have removed all contributions of all algebraic factors, the part that is left is called the primitive part.

    Note that to calculate the primitive part you cannot just divide by the algebraic factors. In the example, (233-1) and (277-1) both have factors of (211-1). If you divide (2231-1) by both of these numbers, you will divide by the factor (211-1) twice, but (2231-1) has this factor only once. Calculation of the primitive primitive part requires compensating for these multiple contributions.

    When we find factors, we report them to Will Edgington according to the primitive part they belong to. Will's files show only the factors of primitive parts directly. To get complete factorizations you must also look up the factors of the algebraic factors.

  43. How is the Primitive Part calculated when the exponent has only distinct odd prime factors?
  44. As described above, we need to account for the multiple contributions that happen because small algebraic factors are themselves factors of multiple large algebraic factors. To organize this, first list all the factors in ranks, where the factors in each rank have the same number of prime factors. For the exponenet 231 (=3 x 7 x 11), there are four ranks:
    1. Three Primes: 231
    2. Two Primes: 21, 33, 77
    3. One Prime: 3, 7, 11
    4. Zero Primes: 1

    The rule is that you multiply by the factors in the first, third, and other odd ranks and divide by the factors in the second, fourth, and other even ranks. Hence the primitive parts of (2231-1) and (2231+1) are, respectively

    (2231-1) * (23-1) * (27-1) * (211-1) / (221-1) / (233-1) / (277-1) / (21-1)
    (2231+1) * (23+1) * (27+1) * (211+1) / (221+1) / (233+1) / (277+1) / (21+1)

  45. Why does this method fail with repeated prime factors?
  46. Consider the case of (2125-1). When we divide this by the algebraic factor (225-1), we have also divided by the algebraic factor (25-1), but we only divided by this factor once. There is no need to also multiply by (25-1) because there has been no multiple division to compensate for.

  47. How is the Primitive Part calculated with repeated factors of the exponent?
  48. First find the product of the distinct odd primes taken only once - this is the "basic" exponent. Form the expression for the primitive part of the number with the basic exponent. Then find the ratio of the exponent to the basic exponent. Increase every exponenent in the expression by this ratio.

    For example, to calculate the primitve part of (21386+1), we first find that the distinct odd primes are 3, 7, and 11, and the basic exponent is 231. The expression for the primitive part of (2231+1) is show above. The multiplicity is 1386 / 231 = 6. Hence the primitive part of (21386+1) is

    (2(231*6)+1) * (2(3*6)+1) * (2(7*6)+1) * (2(11*6)+1) / (2(21*6)+1) / (2(33*6)+1) / (2(77*6)+1) / (2(1*6)+1)

  49. What are "Aurifeuillian Factors"?
  50. Aurifeuillian factors are "kind-of" algebraic factors. They are derived from the polynomial factorization

    4z4+1 = (2z2-2z+1) x (2z2+2z+1)

    For example, when z = 25, we get
    4 x 220+1 = (2 x 210-2 x 25+1) x (2 x 210+2 x 25+1)

    But these coefficients are all multiples of two, so we can write this as
    222+1 = (211-26+1) x (211+26+1)

    To apply this idea to Mersenne numbers, we must also use the fact that
    244-1 = (222-1) x (222+1)

    When the exponent of a Mersenne number is a multiple of 4 but not a multiple of 8, there are Aurifeuillian factors that help factor the number. There are also Aurifeuillian factors for 3n+1 and other cases of an±1, but these Aurifeuillian factors are not relevant to ElevenSmooth. For more information on Aurifeuillian factors, see Section III.C.2 of the book for the Cunningham Project.

  51. What is the divisibility rule for Aurifeuillian Factors?
  52. If "n" is an exponent that has Aurifeuillian factors, and "p" is a prime that is equal to 1 or 7 mod 8, then the "minus factor" for n, usually called Ln, divides the larger minus factor, Lpn. Likewise for the plus factors, called "M", Mn divides Mpn. For the other odd primes, where p is equal 3 or 5 mod 8, there is a "crossover," so Ln divides Mpn and Mn divides Lpn.

    Continuing the examples, for p=7 and n=7*22=154, we have the Aurifeuillian factors:

    (2154+1) = (277-239+1) x (277-239+1)
    (2154+1) = 151115727451278891024385 x 151115727452378402652161

    For p=7 there is no crossover, so L22=1985 divides L154=151115727451278891024385 and M22=2113 divides M154=151115727452378402652161.

    Consider p=3 and n=3*22=66. This has the Aurifeuillian factors:

    (266+1) = (233-217+1) x (233-217+1)
    (266+1) = 8589803521 x 8590065665

    For p=3 there is a crossover, so L22=1985 divides M66=8590065665 and M22=2113 divides L66=8589803521. For a more complete rule covering bases other than 2 and covering larger multiples, see Section III.C of the book on the Cunningham Project. You'll need to be familiar with the Jacobi symbol.

  53. How are Primitive Parts of Aurifeuillian Factors calculated?
  54. Except for the crossover issue, the divisibility and multiplicity issues for Aurifeuilian factors are identical to those issues for algebraic factors. Hence you can proceed in the same manner, determining the basic exponent, listing the factors in ranks, multiplying and dividing factors based on their rank, and apply the ratio. The small complication is that you must determine for each factor whether to use the L-Aurifeuillian (the "minus" one) or the M-Aurifeuillian (the "plus" one) to preserve the divisibility according to the divisibility rule.

  55. How are Aurifeuillian factors used?
  56. Aurifeuillian factors split algebraic factors into two nearly equal components. Aurifeuillian Primitive Parts split Algebraic Primitive Parts into two nearly equal components.

  57. What is the Poisson Approximation?
  58. The standard approximation for situations where there are many independent "opportunities" with a low probability of "success" in each opportunity is the Poisson probability distribution. This says the probability of having exactly "k" successes, if the expected (or average) number of successes is λ (lamda), is

    This approximation becomes exact in the limit, as the number of "opportunities" becomes larger and the probability of success becomes smaller in such a way that the expected number of successes stays constant at λ (lambda). One use of this approximation is estimating the probability that a number has "k" divisors in a range, often for zero divisors in the range. We will also use this approximation below to estimate the probability of zero successes in "N" elliptical curve factoring attempts.

  59. How many factors do we expect a number to have in a size range?
  60. If the size range isn't too near the square root of our number, and we don't know of any other factors, then a reasonable heuristic is to observe that the probability a number "x" is prime is, according to the Prime Number Theorem, about 1/ln(x), and if x is prime, the probability x divides our number is 1/x. Adding this up, the number of primes expected in a range is:

    The ECM algorithm is usually described as working on integers of 15 or 20 or 25 etc digits, depending on the value of B1. Twenty-five digits numbers range from 1024 to 1025, so we can guess that the ECM algorithm will find, roughly, numbers from 1022 to 1027 when working on twenty-five digit numbers. Ln(27/22) = 0.2048, so on average we would expect there to be about one prime factor in this range for every five composites considered. For other ranges the heuristic is:

    Size B1 Expected Size B1 Expected Size B1 Expected
    15 digits 2K 0.3483 35 digits 1M 0.1452 55 digits 110M 0.0918
    20 digits 11K 0.2578 40 digits 3M 0.1268 60 digits 260M 0.0841
    25 digits 50K 0.2048 45 digits 11M 0.1125 65 digits 850M 0.0776
    30 digits 250K 0.1699 50 digits 43M 0.1011 70 digits 2.9G 0.0720

    These numbers apply directly for most of the primitives in the ElevenSmooth project. The major exceptions are those numbers which have Aurifeuillian factors. For those numbers we know a factorization of the primitive, and these estimates apply to each of those factors, resulting in twice as many expected factors of a given size.

  61. What is the expected (average) size of factors in a range?
  62. See MathFAQ

  63. What's the probability of finding a factor in one curve?
  64. First of all, there must really be a factor of the appropriate size; see the earlier question for information about this. Even if the factor exists, the probability of finding it on a particular curve depends on the B2 level as well as the B1 level. A common choice is to set B2 as 100 times B1; Previous versions of GMP-ECM used this convention, the Alpertron Java applet uses this, and ElevenSmooth uses this with Prime95 in the Special Project. Version 5 of GMP-ECM, the program ElevenSmooth uses with the ECM server, has improvements for Stage 2. To take advantage of these improvement, the default B2 value is higher, resulting in a higher probability of finding a factor on each curve. The following table shows the probabilities in the form "1 out of n".

    Size B1 1:100 ECM5 Size B1 1:100 ECM5 Size B1 1:100 ECM5
    15 digits 2K 25 30 35 digits 1M 1800 1100 55 digits 110M 49000 22000
    20 digits 11K 90 90 40 digits 3M 5100 2900 60 digits 260M 124000 52000
    25 digits 50K 300 240 45 digits 11M 10600 5500 65 digits 850M 210000 83000
    30 digits 250K 700 500 50 digits 43M 19300 9000 70 digits 2.9G 340000 120000

  65. What's the probability of finding a factor in "N" curves?
  66. We can use the Poisson Approximation (see above) to answer this question. First we find λ (lambda), the expected (or average) number of times we will find this factor in N trials. This is "N" divided by the appropriate number from the table. We are most interested in the probability of finding the factor zero times (k=0), because subtracting that from one gives the probability of finding the factor one or more times.

    When you perform the "full set" of curves, the value of λ (lamda) is "1", the probabilty of not finding the factor is (1/e), and the probability of finding the factor at least once is 1-(1/e).

  67. What's the probability a number has no factors in a range?
  68. See MathFAQ

  69. What's the probability a residual cofactor will be prime?
  70. See MathFAQ

  71. What's the probability that primes in a range will complete a factorization?
  72. See MathFAQ

  73. What composite numbers are being distributed by the ECM Server?
  74. See MathFAQ

  75. What's the relationship between ElevenSmooth and the Cunningham Project?
  76. Sam Wagstaff, the present keeper of the Cunningham Project, says it ”seeks to factor the numbers bn ± 1 for b = 2, 3, 5, 6, 7, 10, 11, 12, up to high powers n.” The history of the Cunningham Tables has been to extend the base 2 tables in every edition. Because 23,326,400-1 has many algebraic factors, ElevenSmooth finds factors for many exponents, including small exponents such as 21485-1 and 21575-1. You can see the ElevenSmooth factors in Mersenne order by clicking on the Mersenne column header on the Factors Page. So Elevensmooth is, at least philosophically, part of the Cunningham Project and the Cunningham Tables will grow into our factors.

  77. What's the relationship between ElevenSmooth and GIMPS?
  78. The major activity of the Great Internet Mersenne Prime Search (GIMPS) is searching for prime numbers. But there is also a part of GIMPS that is factoring 2n-1 and 2n+1. ElevenSmooth is, at least philosophically, part of this aspect of GIMPS.

  79. Will we find ALL the factors of M(3326400)?
  80. Not unless there is a theoretical breakthrough. Theory provides methods to find factors up to 50 digits (ECM, P-1, P+1), and theory provides methods to factor numbers up to 180 digits (250 digits if they have a special form). Faster hardware and larger networks of computers might raise these limits by 10 or 20 digits, but only the invention of a new factoring technique could take us much beyond that.

  81. When will we quit?
  82. When it isn't fun anymore. Our smallest factors will become candidates for the NFSNET Project after they have been tested for factors up to 50 digits. So even if we stop finding factors, we will be making progress towards the eventual factoring of these numbers.

  83. Why 3326400?
  84. I was originally interested in partial coverings for the Seventeen or Bust project. A covering can be reused if the size of the new covering is a multiple of the old size. For example, a covering of size 36 can be reused within a covering of size 72. I kept multiplying by one more small number until I reached 3,326,400. The possible numbers in a covering of size "n" are exactly the prime factors of 2n-1, so I became interested in the factors of 23,326,400-1. I learned that many factors were unknown but within reach of factoring technology; thus was born the ElevenSmooth Project. None of these additional factors have been useful for Seventeen or Bust, but I've become hooked on finding them.


    Web Questions

  85. How can I recolor GIFs?
  86. I used the free program giftrans to find and change the palette. I wrote the GIFtrans.xls Excel Spreadsheet to automate the color changes. Detailed instructions are in the Recoloring Tutorial.

  87. How can I make favicons?
    1. Download and install the free Icon Edit program.
    2. Start the program and select File/New.
    3. Select Icon/Add Image/16x16 16 color. This size image (16x16) and palette (16 colors) are essential.
    4. Draw your icon.
    5. Select Icon/Add Image/32x32 16 color. This image will be used for a desktop shortcut when users drag the favicon to the desktop.
    6. Draw the 32x32 icon.
    7. Select File/Save As. Name the file "favicon." It will get the file extension ".ico".

  88. How can I get favicons to display?
  89. Copy the file "favicon.ico" to your home directory - the directory with index.html. That's all.

    It is possible to use a different name for the icon file, and it is possible to use different icons on each page. For example, this page should be showing a blue version of the ElevenSmooth icon instead of the standard green version. To display "name.ico" for a page, you must include the following line in the head section of the page:

    <LINK REL="SHORTCUT ICON" HREF="name.ico">

    It is notoriously tricky to test favicons because browsers cache them. Sometimes it helps to select the favicon, drag it a short distance and drop it, repeating five or six times. Sometimes it helps to clear all cached files from the browser.

  90. How can I make a sortable table like on the Factors Page?
  91. Googling "HTML sortable table" will turn up many accolades for Erik Arvidsson's WebFX Sortable Table. Download it and follow the instructions. I found it easy to add new sorting rules for cases that did not exactly fit his three methods. See my sortabletable.js file for more information.

  92. How can I make dynamic cell backgrounds like on the Planner Page?
    1. Give each cell a unique identifier. In the td tag include an "id=" attribute: <td id="Cell1">
    2. In the javascript, use: document.getElementById("Cell1").style.backgroundColor="red";

    You can change the background of an entire row or an entire table by putting the "id" attribute inside the row or table tag.

  93. How do you change the Subject on the Contact Page from different places?
  94. The "Subject" Field on the Contact Page changes based on the link you clicked. For example, this link sets the Subject as Help while this link sets Special Project. The URL for the Contact Page includes an extra string on the end; after "ElevenContact.html" there is a question mark and a short string. In the source code for the page, JavaScript creates the input field using "document.write()" commands. JavaScript reads the short string using "location.search.substring(1)", and writes the <option selected> tag based on comparisons with that value.

  95. How do you change all the Bottom Links without editing every page?
  96. Most pages on this web site have an identical cluster of navigation links on the bottom of the page. As the site grows and evolves, these links change. I make the changes only once to change the links on all pages. If you examine the source code, you will find, at the end,

    <script>BottomLinks();</script>


    This invokes a JavaScript function that creates the links using "document.write()" statements. This JavaScript function is defined in the file "common.js". If you look in the header of each page, you will find the code that includes this file:

    <script type="text/javascript" src="js/common.js"></script>


    The links in the upper right corner of each page are based on the same principle, but there is some additional complexity to change the links slightly from page to page.

  97. How can I make screenshot images?
  98. The Print Screen key will put a bitmap image of the screen into the Windows clipboard. From there you can paste the image into many applications, including PhotoEditor, Paint, and Word. I usually pasted into PhotoEditor (Start>Programs>MicroSoft Office>PhotoEditor), then crop the picture (Images>Crop) to the desired size, then save as JPEG or GIF.

  99. How can I make images of mathematical expressions?
  100. Microsoft Word has a pretty good GUI equation editor. Create an equation by Insert>Object>Microsoft Equation. Use the toolbar to build the expression. When you have the expression built in the Word Document, leave the equation edit mode by clicking outside the equation box. Then select the whole equation box and enter the equation editing box by pulling down Edit>Equation Object>Open. This will open its own window which includes custom sizing through View>Zoom. Select an appropriate size then capture a screen image (see previous question).

  101. How does the Contact Page send mail?
  102. The Contact Page sends me an email every time somebody clicks "Send" - no further action is required by the user. This requires a "server side" function by the computer that is hosting your web site. Of the thousands of functions that can be done "server side," Earthlink only permits three for free, and this is one of them. Earthlink has a basic page and an advanced page describing their system. Your web host probably provides this service, too, although the details may be different.

    If your web host will not provide this service, you can try the HTML Mailto capability. When it works, it opens the user's email program with a pre-composed message. Laurie D.T. Mann has a simple descripion. The Web Design Group has more details, including the advice that "mailto" will fail for many users and information about services.

  103. How did you get the web space for ElevenSmooth?
  104. Most Internet Service Providers (ISPs) provide a small amount of free web space with their accounts. MY ISP, Earthlink, permits up to six email addresses and provides 10 Mbytes of web space with each address. I created a new email address called "ElevenSmooth" and I use those 10 Mbytes.

  105. How did you get the domain name "ElevenSmooth.com" for only $7/year?
  106. I bought the domain name from Web.com I did not buy any additional services.

  107. How did you get free URL Forwarding?
  108. I signed up for the free DNS and domain management account at ZoneEdit.com. Up to five domains can be managed under the free account. Following the ZoneEdit FAQ, I changed the Name Servers and created a Web Forwarding for elevensmooth.com and www.elevensmooth.com.

  109. How can I thank you?
  110. If you find one of these web tips useful, a great way to say "thank you" would be to donate a week of your idle, wasted computer cycles to the ElevenSmooth Project. The Download Page will get you started.


    Other

  111. What do you get out of it?
  112. Every time we find a new factor, there is a small thrill of having learned something that nobody has ever known before - something that the world cares about enough to track. There is also a small thrill of victory over a recalcitrant number that was hiding its factors. There is a satisfaction in using our computers during the idle times that it is normally waiting for keystrokes. There is a sense of history in knowing that we are contributing to a factorization project that has been going on for generations and will continue into the unforeseeable future, each generation using the best tools known at the time to uncover factors of larger and larger numbers. And there is a camraderie with our fellow searchers, having found a few people that share these same passions and pleasures.