a(n) = (21*n^2 + 9*n + 2)/2.

Terms

a(0) =1a(1) =16a(2) =52a(3) =109a(4) =187a(5) =286a(6) =406a(7) =547a(8) =709a(9) =892a(10) =1096a(11) =1321a(12) =1567a(13) =1834a(14) =2122a(15) =2431a(16) =2761a(17) =3112a(18) =3484a(19) =3877a(20) =4291a(21) =4726a(22) =5182a(23) =5659a(24) =6157a(25) =6676a(26) =7216a(27) =7777a(28) =8359a(29) =8962