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

Terms

a(0) =1a(1) =2a(2) =7a(3) =28a(4) =105a(5) =390a(6) =1455a(7) =5432a(8) =20273a(9) =75658a(10) =282359a(11) =1053780a(12) =3932761a(13) =14677262a(14) =54776287a(15) =204427888a(16) =762935265a(17) =2847313170a(18) =10626317415a(19) =39657956492a(20) =148005508553a(21) =552364077718