Given the positive integers, x, y, and z, are consecutive terms of an arithmetic progression, the least value of the positive integer, n,
for which the equation, x^2 – y^2 – z^2 = n, has exactly two solutions is n=27
since 34^2 – 27^2 – 20^2 = 27
and 12^2 – 9^2 – 6^2 = 27.
It turns out that n=1155 is the least value for which there are exactly ten solutions.

How many values of n less than one million have exactly ten distinct solutions?
Source: Project Euler