divisible by , OR OR divisible by
Pythagorean triples are of the form
whereare positive integers with .
If one or both of m and n are even, then C is divisible by 4; otherwise they are both odd and so B would be divisible by 4.
And in this thread
it is proved that 60 divides the product ABC, i.e. 5 (a prime) divides one of A, B, C.