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

Terms

a(0) =1a(1) =4a(2) =16a(3) =60a(4) =225a(5) =840a(6) =3136a(7) =11704a(8) =43681a(9) =163020a(10) =608400a(11) =2270580a(12) =8473921a(13) =31625104a(14) =118026496a(15) =440480880a(16) =1643897025a(17) =6135107220a(18) =22896531856a(19) =85451020204a(20) =318907548961