38167092497domain: NAppears in sequencesDivisorial primes: Primes p such that p = 1 + Product_{d|n} d for some n (ordered by n).at n=28A118370Primes p such that all prime factors of p-1 have exponent 4.at n=21A188717Divisorial primes p such that p-1 = Product_{d|k} d for some k < sqrt(p-1).at n=13A258897