Numbers of the form ((6k+5)^2+9)/2 or 2(3k+4)^2-9.

Terms

a(0) =17a(1) =23a(2) =65a(3) =89a(4) =149a(5) =191a(6) =269a(7) =329a(8) =425a(9) =503a(10) =617a(11) =713a(12) =845a(13) =959a(14) =1109a(15) =1241a(16) =1409a(17) =1559a(18) =1745a(19) =1913a(20) =2117a(21) =2303a(22) =2525a(23) =2729a(24) =2969a(25) =3191a(26) =3449a(27) =3689a(28) =3965a(29) =4223