a(n) = -24*A015219(n-2)*a(n-1), with a(1) = 2.A203778a(n) = -24*A015219(n-2)*a(n-1), with a(1) = 2.Terms a(0) =2a(1) =-48a(2) =40320a(3) =-159667200External referencesoeis: A203778