458473480079domain: NAppears in sequencesa(n) = (a(n-1) * a(n-5) + a(n-2) * a(n-4) + a(n-3)^2) / a(n-6), a(0) = a(1) = a(2) = a(3) = 1, a(4) = a(5) = 2.at n=20A227999