181397domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumber of ordered 5-tuples of integers from [ 1,n ] with no common factors among quadruples.at n=28A015653Primes p such that p+2, (p^2-1)/2+p and (p^2+3)/2+3*p are also prime.at n=41A352948Prime numbersat n=16443