a(n) = n^3*(n+1)^2*(n+2)/12.

Terms

a(0) =1a(1) =24a(2) =180a(3) =800a(4) =2625a(5) =7056a(6) =16464a(7) =34560a(8) =66825a(9) =121000a(10) =207636a(11) =340704a(12) =538265a(13) =823200a(14) =1224000a(15) =1775616a(16) =2520369a(17) =3508920a(18) =4801300a(19) =6468000a(20) =8591121a(21) =11265584a(22) =14600400a(23) =18720000a(24) =23765625a(25) =29896776a(26) =37292724a(27) =46154080a(28) =56704425a(29) =69192000