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

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =88a(6) =370a(7) =1607a(8) =7150a(9) =32418a(10) =149246a(11) =695840a(12) =3278942a(13) =15591708a(14) =74721660a(15) =360540041a(16) =1750069638a(17) =8539926158a(18) =41869742140a(19) =206149706634