Digit '9' concatenated with a(n) is a prime.

Terms

a(0) =7a(1) =11a(2) =19a(3) =29a(4) =37a(5) =41a(6) =47a(7) =53a(8) =67a(9) =71a(10) =77a(11) =83a(12) =91a(13) =97a(14) =103a(15) =109a(16) =127a(17) =133a(18) =137a(19) =151a(20) =157a(21) =161a(22) =173a(23) =181a(24) =187a(25) =199a(26) =203a(27) =209a(28) =221a(29) =227