1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6 + 8*n^7 + 9*n^8.

Terms

a(0) =1a(1) =45a(2) =4097a(3) =83653a(4) =757305a(5) =4272461a(6) =17736745a(7) =59409477a(8) =169826513a(9) =429794605a(10) =987654321a(11) =2098573445a(12) =4178995657a(13) =7879732173a(14) =14181546905a(15) =24517448581a(16) =40926266145a(17) =66242446637a(18) =104327377633a(19) =160347899205a(20) =241108033241