Expansion of (1-2x+6x^2-x^3)/(1-3x+x^2)^2.

Terms

a(0) =1a(1) =4a(2) =19a(3) =75a(4) =264a(5) =869a(6) =2741a(7) =8396a(8) =25175a(9) =74271a(10) =216336a(11) =623689a(12) =1782889a(13) =5060500a(14) =14277019a(15) =40070259a(16) =111954456a(17) =311555501a(18) =863978525a(19) =2388417116a(20) =6584117471a(21) =18104432199a(22) =49667825184a(23) =135974484625a(24) =371543306449