Expansion of x*(1+x)/(1 -2*x -9*x^2).

Terms

a(0) =1a(1) =3a(2) =15a(3) =57a(4) =249a(5) =1011a(6) =4263a(7) =17625a(8) =73617a(9) =305859a(10) =1274271a(11) =5301273a(12) =22070985a(13) =91853427a(14) =382345719a(15) =1591372281a(16) =6623856033a(17) =27570062595a(18) =114754829487a(19) =477640222329