Expansion of g.f. (2-3*x-x^2)/((1-x^2)*(1-3*x)).

Terms

a(0) =2a(1) =3a(2) =10a(3) =27a(4) =82a(5) =243a(6) =730a(7) =2187a(8) =6562a(9) =19683a(10) =59050a(11) =177147a(12) =531442a(13) =1594323a(14) =4782970a(15) =14348907a(16) =43046722a(17) =129140163a(18) =387420490a(19) =1162261467a(20) =3486784402a(21) =10460353203a(22) =31381059610a(23) =94143178827a(24) =282429536482a(25) =847288609443