E.g.f.: exp(x/(1 - x)) / (1 + x).

Terms

a(0) =1a(1) =0a(2) =3a(3) =4a(4) =57a(5) =216a(6) =2755a(7) =18348a(8) =247569a(9) =2368432a(10) =35256771a(11) =436248660a(12) =7235178313a(13) =108919083144