Integers k such that 10^k - 39 is prime.

Terms

a(0) =2a(1) =5a(2) =6a(3) =12a(4) =17a(5) =19a(6) =61a(7) =102a(8) =195a(9) =447a(10) =1250a(11) =1329a(12) =1935a(13) =3930a(14) =5837a(15) =7176a(16) =8724a(17) =20881a(18) =23936a(19) =61868a(20) =91920