Divisible only by primes congruent to 4 mod 7.

Terms

a(0) =1a(1) =11a(2) =53a(3) =67a(4) =109a(5) =121a(6) =137a(7) =151a(8) =179a(9) =193a(10) =263a(11) =277a(12) =347a(13) =389a(14) =431a(15) =487a(16) =557a(17) =571a(18) =583a(19) =599a(20) =613a(21) =641a(22) =683a(23) =737a(24) =739a(25) =809a(26) =823a(27) =907a(28) =977a(29) =991