a(n) = 81*n^2 - 44*n + 6.

Terms

a(0) =6a(1) =43a(2) =242a(3) =603a(4) =1126a(5) =1811a(6) =2658a(7) =3667a(8) =4838a(9) =6171a(10) =7666a(11) =9323a(12) =11142a(13) =13123a(14) =15266a(15) =17571a(16) =20038a(17) =22667a(18) =25458a(19) =28411a(20) =31526a(21) =34803a(22) =38242a(23) =41843a(24) =45606a(25) =49531a(26) =53618a(27) =57867a(28) =62278a(29) =66851