Expansion of (1-x)*(1+x)/(1-2*x-x^2+x^3).

Terms

a(0) =1a(1) =2a(2) =4a(3) =9a(4) =20a(5) =45a(6) =101a(7) =227a(8) =510a(9) =1146a(10) =2575a(11) =5786a(12) =13001a(13) =29213a(14) =65641a(15) =147494a(16) =331416a(17) =744685a(18) =1673292a(19) =3759853a(20) =8448313a(21) =18983187a(22) =42654834a(23) =95844542a(24) =215360731a(25) =483911170a(26) =1087338529a(27) =2443227497a(28) =5489882353a(29) =12335653674