a(n) = n^4 + (9/2)*n^3 + n^2 - (9/2)*n + 1.

Terms

a(0) =1a(1) =3a(2) =48a(3) =199a(4) =543a(5) =1191a(6) =2278a(7) =3963a(8) =6429a(9) =9883a(10) =14556a(11) =20703a(12) =28603a(13) =38559a(14) =50898a(15) =65971a(16) =84153a(17) =105843a(18) =131464a(19) =161463a(20) =196311a(21) =236503a(22) =282558a(23) =335019a(24) =394453a(25) =461451a(26) =536628a(27) =620623a(28) =714099a(29) =817743