a(n) = 12*n^2 - 8*n + 9.

Terms

a(0) =13a(1) =41a(2) =93a(3) =169a(4) =269a(5) =393a(6) =541a(7) =713a(8) =909a(9) =1129a(10) =1373a(11) =1641a(12) =1933a(13) =2249a(14) =2589a(15) =2953a(16) =3341a(17) =3753a(18) =4189a(19) =4649a(20) =5133a(21) =5641a(22) =6173a(23) =6729a(24) =7309a(25) =7913a(26) =8541a(27) =9193a(28) =9869a(29) =10569