MathDB
11 and 31 divides sums of powers

Source: Canada Repêchage 2016/1

June 19, 2016
number theory

Problem Statement

(a) Find all positive integers nn such that 11(3n+4n)11|(3^n + 4^n).
(b) Find all positive integers nn such that 31(4n+7n+20n)31|(4^n + 7^n + 20^n).