Numbers k such that 10^k + 9 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =9a(5) =18a(6) =22a(7) =45a(8) =49a(9) =56a(10) =69a(11) =146a(12) =202a(13) =272a(14) =2730a(15) =2841a(16) =4562a(17) =31810a(18) =43186a(19) =48109a(20) =92691a(21) =237670a(22) =400310a(23) =482706a(24) =831776