E.g.f. 1/(1-x^2-x^3).

Terms

a(0) =1a(1) =0a(2) =2a(3) =6a(4) =24a(5) =240a(6) =1440a(7) =15120a(8) =161280a(9) =1814400a(10) =25401600a(11) =359251200a(12) =5748019200a(13) =99632332800