3512737domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = Sum_{k=1..n-1}((k mod 5)*a(n-k)), a(1) = 1.at n=17A259714Number of factorizations of m^n into exactly four factors, where m is a product of two distinct primes.at n=36A277240Prime numbersat n=250989