a(n) = n*(n+1)*(n+7)*(122+57*n+n^2)/120.

Terms

a(0) =24a(1) =108a(2) =302a(3) =671a(4) =1296a(5) =2275a(6) =3724a(7) =5778a(8) =8592a(9) =12342a(10) =17226a(11) =23465a(12) =31304a(13) =41013a(14) =52888a(15) =67252a(16) =84456a(17) =104880a(18) =128934a(19) =157059a(20) =189728a(21) =227447a(22) =270756a(23) =320230a(24) =376480a(25) =440154a(26) =511938a(27) =592557a(28) =682776a(29) =783401