There are squares that lie between 22n and 22(n+1)
These are two consecutive even powers of two.
The difference between two consecutive squares is always some odd number 2k+1.
Give that 22n and 22(n+1) are two squares:
2n-1 is the number of squares between them.
2n is the number of odd number increments
2(2n+1) + 2(2n-2) is the "middle" square
2n + 2(n-1) is the root of 2(2n+1) + 2(2n-2)
Example1: n = 1, 22n = 4, 22(n+1) = 16
2(2n+1) + 2(2n-2) = 9, 2n + 2(n-1) = 3
Example2: n = 2, 22n = 16, 22(n+1) = 64
2(2n+1) + 2(2n-2) = 36, 2n + 2(n-1) = 6
22n + 2(n+1) + 1 is another square with a root of 2n + 1
22n - 2(n+1) + 1 is another square with a root of 2n - 1