Numbers k such that 7*10^k - 9 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =14a(5) =15a(6) =23a(7) =28a(8) =54a(9) =100a(10) =272a(11) =373a(12) =403a(13) =568a(14) =639a(15) =842a(16) =969a(17) =1255a(18) =1259a(19) =3047a(20) =4838a(21) =6389a(22) =12755a(23) =15142a(24) =34943a(25) =37652a(26) =38108a(27) =38686a(28) =39384a(29) =43393