11*n^2 + 11*n + 3.

Terms

a(0) =3a(1) =25a(2) =69a(3) =135a(4) =223a(5) =333a(6) =465a(7) =619a(8) =795a(9) =993a(10) =1213a(11) =1455a(12) =1719a(13) =2005a(14) =2313a(15) =2643a(16) =2995a(17) =3369a(18) =3765a(19) =4183a(20) =4623a(21) =5085a(22) =5569a(23) =6075a(24) =6603a(25) =7153a(26) =7725a(27) =8319a(28) =8935a(29) =9573