13005619200domain: NAppears in sequencesa(n) = (n!)^2*n.at n=8A084915a(0) = 0; a(1) = 1; if n is odd then a(n) = 2*a(n-1) - (n-1)*a(n-2) otherwise a(n) = 2*(a(n-1) - (n-2)*a(n-2)).at n=20A122598