27 Apr
2010
27 Apr
'10
5:21 p.m.
I've been playing with commutators lately, and the following puzzle turned up ... Suppose A and B are integers > 1. When is A^B / B^A an integer? What values are possible? Clearly A and B must have the same prime divisors, but the primes can occur to different powers. A = 45, B = 75 is a suggestive example. Rich