Revert transform of 2*x*(1 - x + x^4 - x^5 + x^6)-x/(1+x).

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =31a(5) =113a(6) =429a(7) =1679a(8) =6719a(9) =27367a(10) =113053a(11) =472471a(12) =1993785a(13) =8483023a(14) =36348595a(15) =156705421a(16) =679218965a(17) =2957961685a(18) =12936141935a(19) =56787742645a(20) =250137441355