Expansion of g.f.: 1/(1 + 2*x + 9*x^2).

Terms

a(0) =1a(1) =-2a(2) =-5a(3) =28a(4) =-11a(5) =-230a(6) =559a(7) =952a(8) =-6935a(9) =5302a(10) =51811a(11) =-151340a(12) =-163619a(13) =1689298a(14) =-1906025a(15) =-11391632a(16) =39937489a(17) =22649710a(18) =-404736821a(19) =605626252a(20) =2431378885a(21) =-10313394038a(22) =-1255621889a(23) =95331790120a(24) =-179362983239a(25) =-499260144602a(27) =-732232975292