853471domain: NAppears in sequencesProduct p*q of two primes with q = 2*p + 1.at n=28A156592Numbers n such that A229964(n) = 1.at n=31A229965Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.at n=35A231966Triangular numbers that are emirpimes.at n=21A375385