Expansion of (1+x-x^2)/(1-2x-2x^2+x^4).

Terms

a(0) =1a(1) =3a(2) =7a(3) =20a(4) =53a(5) =143a(6) =385a(7) =1036a(8) =2789a(9) =7507a(10) =20207a(11) =54392a(12) =146409a(13) =394095a(14) =1060801a(15) =2855400a(16) =7685993a(17) =20688691a(18) =55688567a(19) =149899116a(20) =403489373a(21) =1086088287a(22) =2923466753a(23) =7869210964a(24) =21181866061a(25) =57016065763a(26) =153472396895