G.f. satisfies A(x) = 1 + x*A(x) - x^2*A(x)^4.

Terms

a(0) =1a(1) =1a(2) =0a(3) =-4a(4) =-10a(5) =2a(6) =89a(7) =249a(8) =-91a(9) =-2811a(10) =-8071a(11) =4201a(12) =103617a(13) =297201a(14) =-200421a(15) =-4167581a(16) =-11798389a(17) =9803475a(18) =177275251a(19) =492087227a(20) =-488311177a(21) =-7839760737a(22) =-21249466773a(23) =24651743523a(24) =356735365223a(25) =941396264159