5853241domain: NPropertiesPrimalityPrimeyesAppears in sequencesQuintuple Hex-primes: let f(n) = A102489(n); then sequence lists primes p such that f(p), f(f(p)), f(f(f(p))), f(f(f(f(p)))) and f(f(f(f(f(p))))) are also primes.at n=21A237441Prime numbersat n=403421