List all integers n such that the sum 2^2 + 3^2 + 4^2 + ... + n^2
equals a prime number.
p&p solutions only.
Should you have: "the second factor is always > 6"?
I meant 'the reduced second factor' but your text is clearer.
be coherent with defining (n-1)/6 as the 1st factor
I mentioned reducing the first factor and explicitly showed division by factors of 6.
Posted by xdog
on 2017-01-14 07:50:35