a(n) = n*(n+1)*(9*n^2 - n - 5)/6.

Terms

a(0) =0a(1) =1a(2) =29a(3) =146a(4) =450a(5) =1075a(6) =2191a(7) =4004a(8) =6756a(9) =10725a(10) =16225a(11) =23606a(12) =33254a(13) =45591a(14) =61075a(15) =80200a(16) =103496a(17) =131529a(18) =164901a(19) =204250a(20) =250250a(21) =303611a(22) =365079a(23) =435436a(24) =515500a(25) =606125a(26) =708201a(27) =822654a(28) =950446a(29) =1092575