Expansion of 1/((1+x*(1-M(x)))*sqrt(1-2*x-3*x^2)), M(x) the g.f. of A001006.

Terms

a(0) =1a(1) =1a(2) =4a(3) =10a(4) =29a(5) =82a(6) =236a(7) =681a(8) =1975a(9) =5745a(10) =16757a(11) =48982a(12) =143442a(13) =420721a(14) =1235663a(15) =3633453a(16) =10695292a(17) =31511524a(18) =92919758a(19) =274203662a(20) =809719718a(21) =2392579638a(22) =7073684393a(23) =20924387460a(24) =61925598216a(25) =183350728661a(26) =543095661673