# Problem 152: Writing 1/2 as a sum of inverse squares
There are several ways to write the number 1/2 as a sum of inverse
squares using distinct integers. For instance, the numbers
{2,3,4,5,7,12,15,20,28,35} can be used: In fact, only using integers
between 2 and 45 inclusive, there are exactly three ways to do it, the
remaining two being: {2,3,4,6,7,9,10,20,28,35,36,45} and
{2,3,4,6,7,9,12,15,28,30,35,36,45}. How many ways are there to write the
number 1/2 as a sum of inverse squares using distinct integers between 2
and 80 inclusive?