551286domain: NAppears in sequencesa(n) = (4*n+1)*(4*n+2)*(4*n+3).at n=20A001505a(n) = (5*n + 1)*(5*n + 2)*(5*n + 3).at n=16A001509a(n) = 3*n*(3*n + 1)*(3*n + 2).at n=26A228889