a(n) = 4*n^2 + 4*n - 7.

Terms

a(0) =1a(1) =17a(2) =41a(3) =73a(4) =113a(5) =161a(6) =217a(7) =281a(8) =353a(9) =433a(10) =521a(11) =617a(12) =721a(13) =833a(14) =953a(15) =1081a(16) =1217a(17) =1361a(18) =1513a(19) =1673a(20) =1841a(21) =2017a(22) =2201a(23) =2393a(24) =2593a(25) =2801a(26) =3017a(27) =3241a(28) =3473a(29) =3713