Series reversion of x*(1-3*x)/(1-x).

Terms

a(0) =1a(1) =2a(2) =10a(3) =62a(4) =430a(5) =3194a(6) =24850a(7) =199910a(8) =1649350a(9) =13879538a(10) =118669210a(11) =1027945934a(12) =9002083870a(13) =79568077034a(14) =708911026210