Numbers k such that (7*10^k + 197)/3 is prime.

Terms

a(0) =1a(1) =3a(2) =4a(3) =6a(4) =7a(5) =52a(6) =53a(7) =103a(8) =131a(9) =199a(10) =294a(11) =426a(12) =780a(13) =1144a(14) =1876a(15) =2001a(16) =3507a(17) =5737a(18) =6657a(19) =12558a(20) =28303a(21) =31608a(22) =60643a(23) =74741a(24) =124648