Numbers k such that (56*10^k - 47)/9 is prime.

Terms

a(0) =2a(1) =3a(2) =6a(3) =9a(4) =27a(5) =48a(6) =60a(7) =74a(8) =161a(9) =242a(10) =269a(11) =518a(12) =1092a(13) =1220a(14) =1883a(15) =2618a(16) =3266a(17) =6699a(18) =8855a(19) =17022a(20) =17454a(21) =101222