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

Terms

a(0) =1a(1) =3a(2) =6a(3) =12a(4) =21a(5) =33a(6) =50a(7) =72a(8) =99a(9) =133a(10) =174a(11) =222a(12) =279a(13) =345a(14) =420a(15) =506a(16) =603a(17) =711a(18) =832a(19) =966a(20) =1113a(21) =1275a(22) =1452a(23) =1644a(24) =1853a(25) =2079a(26) =2322a(27) =2584a(28) =2865a(29) =3165