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

Terms

a(0) =0a(1) =1a(2) =0a(3) =6a(4) =8a(5) =30a(6) =60a(7) =154a(8) =336a(9) =774a(10) =1700a(11) =3762a(12) =8184a(13) =17758a(14) =38220a(15) =81930a(16) =174752a(17) =371382a(18) =786420a(19) =1660258a(20) =3495240a(21) =7340046a(22) =15379100a(23) =32156346a(24) =67108848a(25) =139810150a(26) =290805060a(27) =603979794a(28) =1252698776a(29) =2594876094