MathDB

gcd (5^m + 7^m, 5^n + 7^n) for m,n coprime

Source: 2014 Brazil IMO TST 3.1

July 23, 2021

number theorygreatest common divisorGCD

Problem Statement

For

m

and

n

positive integers that are prime to each other, determine the possible values of

\gcd (5^m + 7^m, 5^n + 7^n)