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

Terms

a(0) =1a(1) =-1a(2) =-2a(3) =5a(4) =12a(5) =-41a(6) =-89a(7) =391a(8) =733a(9) =-4051a(10) =-6320a(11) =44120a(12) =54990a(13) =-496406a(14) =-465932a(15) =5710408a(16) =3637847a(17) =-66714699a(18) =-22683218a(19) =787957397a(20) =35371351a(21) =-9376925921a(22) =2356626520a(23) =112147043475a(24) =-61910867756