MathDB
GCD greater than GCD

Source: Canada Repêchage 2016/6

June 19, 2016
number theorygreatest common divisor

Problem Statement

Determine all ordered triples of positive integers (x,y,z)(x, y, z) such that gcd(x+y,y+z,z+x)>gcd(x,y,z)\gcd(x+y, y+z, z+x) > \gcd(x, y, z).