Pivotal Square Sums
Problem 261
Let us call a positive integer k a square-pivot, if there is a pair of integers m > 0 and n ≥ k, such that the sum of the (m+1) consecutive squares up to k equals the sum of the m consecutive squares from (n+1) on:
(k-m)2 + ... + k2 = (n+1)2 + ... + (n+m)2.
Some small square-pivots are
Find the sum of all distinct square-pivots ≤ 1010.