Numbers k such that (4*10^k - 19)/3 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =8a(6) =42a(7) =52a(8) =81a(9) =96a(10) =98a(11) =152a(12) =190a(13) =261a(14) =686a(15) =1930a(16) =2152a(17) =5694a(18) =6341a(19) =14067a(20) =18124a(21) =31678a(22) =58521a(23) =73647a(24) =128244