109726domain: NAppears in sequencesa(n) = (Sum_{j=1..h-1} a(n-j) + a(n-1)*a(n-h+1))/a(n-h) with a(1), ..., a(h)=1, where h = 6.at n=15A283960Centered pentagonal numbers which are products of three distinct primes.at n=38A364610