Numbers k such that (49*10^k - 139)/9 is prime.

Terms

a(0) =5a(1) =6a(2) =18a(3) =27a(4) =48a(5) =51a(6) =92a(7) =396a(8) =678a(9) =1259a(10) =2085a(11) =2820a(12) =3009a(13) =4311a(14) =5015a(15) =7775a(16) =7955a(17) =8595a(18) =120380a(19) =166721