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

Terms

a(0) =2a(1) =4a(2) =8a(3) =16a(4) =28a(5) =48a(6) =84a(7) =144a(8) =244a(9) =416a(10) =708a(11) =1200a(12) =2036a(13) =3456a(14) =5860a(15) =9936a(16) =16852a(17) =28576a(18) =48452a(19) =82160a(20) =139316a(21) =236224a(22) =400548a(23) =679184a(24) =1151636a(25) =1952736a(26) =3311108a(27) =5614384a(28) =9519860a(29) =16142080