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

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =20a(5) =72a(6) =271a(7) =1055a(8) =4212a(9) =17152a(10) =70966a(11) =297482a(12) =1260715a(13) =5392627a(14) =23251149a(15) =100947165a(16) =440939300a(17) =1936388032a(18) =8544353718a(19) =37863744762a(20) =168438633954a(21) =751927422662