Numbers k such that (2*10^k - 197)/3 is prime.

Terms

a(0) =3a(1) =5a(2) =17a(3) =20a(4) =21a(5) =107a(6) =176a(7) =207a(8) =2115a(9) =2156a(10) =2571a(11) =4082a(12) =5291a(13) =7148a(14) =7525a(15) =16857a(16) =23245a(17) =23347a(18) =31307a(19) =35107a(20) =54527