Andrew Tomazos schrieb: > It's clear that q is an integer, but how do you know that (c + a / q) > and (c - a / q) are both perfect squares? That is required if n and m > are to be integers. > -Andrew. > Btw, the German Wiki on the topic also contains the sqrt formula. And their q is always 2, and they assume that a, b and c are primitive.