Exponential generating function = (1+x)^(1+x^2).

Terms

a(0) =1a(1) =1a(2) =0a(3) =6a(4) =12a(5) =-20a(6) =420a(7) =-252a(8) =-336a(9) =66960a(10) =-368640a(11) =2328480a(12) =2898720a(13) =-117767520a(14) =1720764864a(15) =-12297479040a(16) =58230547200a(17) =312819736320