G.f. satisfies A(x) = 1 + x*(1 + 1/A(x)^3).

Terms

a(0) =1a(1) =2a(2) =-6a(3) =42a(4) =-350a(5) =3234a(6) =-31878a(7) =328426a(8) =-3494142a(9) =38093442a(10) =-423344966a(11) =4778162922a(12) =-54621614814a(13) =631114404258