MathDB

Problem 2

Part of 1968 Yugoslav Team Selection Test

Problems(1)

(n-2)!=an+1 iff n prime

Source: Yugoslav TST 1968 P2

5/29/2021
Let n>3n>3 be a positive integer. Prove that nn is prime if and only if there exists a positive integer α\alpha such that n!=n(n−1)(αn+1)n!=n(n-1)(\alpha n+1).
number theory