91466933731domain: NAppears in sequencesa(0..4) = 1 and a(n) = (a(n-2)^2 + a(n-3)^2 + a(n-2)*(3*a(n-3) + a(n-4)) + a(n-1)*(a(n-3) - a(n-5)))/(a(n-4) + a(n-5)) for n > 4.at n=18A376024