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

Terms

a(0) =0a(1) =1a(2) =8a(3) =24a(4) =52a(5) =95a(6) =156a(7) =238a(8) =344a(9) =477a(10) =640a(11) =836a(12) =1068a(13) =1339a(14) =1652a(15) =2010a(16) =2416a(17) =2873a(18) =3384a(19) =3952a(20) =4580a(21) =5271a(22) =6028a(23) =6854a(24) =7752a(25) =8725a(26) =9776a(27) =10908a(28) =12124a(29) =13427