#!/usr/bin/ruby # Let b(n) be the smallest odd composite k such that q^((k-1)/2) == -1 (mod k) for every prime q <= prime(n). func isok(n, k) { n.prime.primes.all {|q| powmod(q, (k-1)/2, k) == k-1 } } say isok(7, 614796634515444067)
