152587500001domain: NAppears in sequencesLargest prime factor of 5^n + 1.at n=24A074478Primes of the form Phi(k, -5), where Phi is the cyclotomic polynomial.at n=9A291998Primes of the form Phi(k, 5), where Phi is the cyclotomic polynomial.at n=9A292009a(n) is the largest prime factor of n^n - n.at n=23A372229