a(n) = 2*n^2 + 1.

Terms

a(0) =1a(1) =3a(2) =9a(3) =19a(4) =33a(5) =51a(6) =73a(7) =99a(8) =129a(9) =163a(10) =201a(11) =243a(12) =289a(13) =339a(14) =393a(15) =451a(16) =513a(17) =579a(18) =649a(19) =723a(20) =801a(21) =883a(22) =969a(23) =1059a(24) =1153a(25) =1251a(26) =1353a(27) =1459a(28) =1569a(29) =1683