Expansion of E.g.f. x*(1-x)/(1-x-x^3).

Terms

a(0) =0a(1) =1a(2) =0a(3) =0a(4) =24a(5) =120a(6) =720a(7) =10080a(8) =120960a(9) =1451520a(10) =21772800a(11) =359251200a(12) =6227020800a(13) =118313395200