Prove that if for a positive integer $n$ is $5^n + 3^n + 1$ is prime number, then $n$ is divided by $12$.
Problem
Source: 1998 Estonia National Olympiad Final Round grade 10 p4
Tags: primes, divided, number theory, divisible
Source: 1998 Estonia National Olympiad Final Round grade 10 p4
Tags: primes, divided, number theory, divisible
Prove that if for a positive integer $n$ is $5^n + 3^n + 1$ is prime number, then $n$ is divided by $12$.