Numbers k such that 9*10^k + 7 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =15a(6) =19a(7) =20a(8) =46a(9) =52a(10) =53a(11) =192a(12) =380a(13) =588a(14) =776a(15) =906a(16) =1350a(17) =1736a(18) =2914a(19) =7508a(20) =15710a(21) =16453a(22) =17488a(23) =18109a(24) =21604a(25) =25891a(26) =26725a(27) =34838a(28) =67468