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

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =90a(6) =393a(7) =1789a(8) =8378a(9) =40050a(10) =194492a(11) =956448a(12) =4752519a(13) =23822571a(14) =120315345a(15) =611644737a(16) =3127389106a(17) =16072642890a(18) =82981119252a(19) =430187414196