G.f. satisfies A(x) = (1 + x) * (1 - x*A(x)^2).

Terms

a(0) =1a(1) =0a(2) =-1a(3) =2a(4) =-2a(5) =-1a(6) =9a(7) =-20a(8) =20a(9) =24a(10) =-150a(11) =327a(12) =-293a(13) =-599a(14) =3097a(15) =-6452a(16) =4854a(17) =15878a(18) =-71252a(19) =140112a(20) =-81328a(21) =-437346a(22) =1746254a(23) =-3214989a(24) =1223971a(25) =12345295a(26) =-44552833a(27) =76242173a(28) =-11292089a(29) =-354175849