Revert transform of (-1 + 2x + x^2)/(-1 + x + 2x^2 + x^3).

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =88a(6) =369a(7) =1597a(8) =7078a(9) =31966a(10) =146592a(11) =680826a(12) =3195883a(13) =15138737a(14) =72274885a(15) =347411257a(16) =1679958814a(17) =8166820486a(18) =39889343392a(19) =195658510368a(20) =963381098208