Prove that there exist infinitely many positive integers $ n$ such that $ n!$ is not divisible by $ n^2+1$.
Problem
Source: Indonesia TST 2009 First Stage Test 2 Problem 4
Tags: number theory proposed, number theory
Source: Indonesia TST 2009 First Stage Test 2 Problem 4
Tags: number theory proposed, number theory
Prove that there exist infinitely many positive integers $ n$ such that $ n!$ is not divisible by $ n^2+1$.