Divisible only by primes congruent to 3 mod 8.

Terms

a(0) =1a(1) =3a(2) =9a(3) =11a(4) =19a(5) =27a(6) =33a(7) =43a(8) =57a(9) =59a(10) =67a(11) =81a(12) =83a(13) =99a(14) =107a(15) =121a(16) =129a(17) =131a(18) =139a(19) =163a(20) =171a(21) =177a(22) =179a(23) =201a(24) =209a(25) =211a(26) =227a(27) =243a(28) =249a(29) =251