Revert transform of 2*x*(1 - x - x^3 + x^4)-x/(1+x).

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =43a(5) =181a(6) =799a(7) =3641a(8) =17013a(9) =81069a(10) =392427a(11) =1924363a(12) =9539431a(13) =47726001a(14) =240671423a(15) =1222026809a(16) =6242470529a(17) =32058889049a(18) =165425745315a(19) =857247711523