Question 53
A triangular number is one of the numbers $1, 3, 6, 10, 15, \ldots$ of the form $T_{n} = 1 + 2 + \cdots + n$ or, equivalently, $T_{n} = \left(n^{2} + n\right) / 2$.
Find, with proof, all ways of writing $2015$ as the difference of two triangular numbers.
Find, with proof, all ways of writing $2015$ as the difference of two triangular numbers.