Primitive Pythagorean triple (source code)

= Primitive Pythagorean triple

A <Pythagorean triple> $(a,b,c)$ whose coordinates have <greatest common divisor> 1. Its two legs have opposite <integer parity>, and every <Pythagorean triple> is a unique <positive integer> multiple of a <primitive Pythagorean triple> up to the ordering of its legs.