Problem
ALG-B1-M12-P029 Variant 8, Problem 1
#29
★★★★★ Level 5 of 5
Find all integers \(n\) for which \(n^4+4\) is prime.
Sophie Germain factorization.
\(n^4+4=(n^2-2n+2)(n^2+2n+2)\). Prime only for \(n=\pm1\).
Mock olympiad problem. Tags: prime, factorisation.