Numbers k such that 15*10^k + 1 is prime.

Terms

a(0) =1a(1) =4a(2) =7a(3) =8a(4) =18a(5) =19a(6) =73a(7) =143a(8) =192a(9) =408a(10) =533a(11) =792a(12) =3179a(13) =7709a(14) =9554a(15) =35598a(16) =41587a(17) =52919a(18) =56021a(19) =61604a(20) =78672a(21) =81624