Numbers k such that (43*10^k + 47)/9 is prime.

Terms

a(0) =1a(1) =3a(2) =7a(3) =12a(4) =15a(5) =21a(6) =85a(7) =177a(8) =204a(9) =477a(10) =487a(11) =1686a(12) =2179a(13) =2815a(14) =2892a(15) =3466a(16) =7308a(17) =17883a(18) =25431a(19) =69048a(20) =89169a(21) =126441