a(n) = n*(n^4 + 30*n^3 + 395*n^2 + 2910*n + 11064)/120.

Terms

a(0) =0a(1) =120a(2) =312a(3) =606a(4) =1040a(5) =1661a(6) =2526a(7) =3703a(8) =5272a(9) =7326a(10) =9972a(11) =13332a(12) =17544a(13) =22763a(14) =29162a(15) =36933a(16) =46288a(17) =57460a(18) =70704a(19) =86298a(20) =104544a(21) =125769a(22) =150326a(23) =178595a(24) =210984a(25) =247930a(26) =289900a(27) =337392a(28) =390936a(29) =451095