Expansion of g.f. (2+7*x+2*x^2)/((x^2-1)*(1+4*x+x^2)).

Terms

a(0) =-2a(1) =1a(2) =-6a(3) =16a(4) =-62a(5) =225a(6) =-842a(7) =3136a(8) =-11706a(9) =43681a(10) =-163022a(11) =608400a(12) =-2270582a(13) =8473921a(14) =-31625106a(15) =118026496a(16) =-440480882a(17) =1643897025a(18) =-6135107222a(19) =22896531856a(20) =-85451020206a(21) =318907548961