a(n) = (3+n)*(2 + 33*n + n^2)/6.

Terms

a(0) =1a(1) =24a(2) =60a(3) =110a(4) =175a(5) =256a(6) =354a(7) =470a(8) =605a(9) =760a(10) =936a(11) =1134a(12) =1355a(13) =1600a(14) =1870a(15) =2166a(16) =2489a(17) =2840a(18) =3220a(19) =3630a(20) =4071a(21) =4544a(22) =5050a(23) =5590a(24) =6165a(25) =6776a(26) =7424a(27) =8110a(28) =8835a(29) =9600