MathDB
7^{n-1} - 3^{n-1} is divisible by n, non prime n

Source: 2015 Saudi Arabia BMO TST II p4

July 24, 2020
dividesdivisiblenumber theory

Problem Statement

Prove that there exist infinitely many non prime positive integers nn such that 7n−1−3n−17^{n-1} - 3^{n-1} is divisible by nn.
Lê Anh Vinh
Back to ProblemsView on AoPS