Primes having only {0, 4, 9} as digits.

Terms

a(0) =409a(1) =449a(2) =499a(3) =4049a(4) =4099a(5) =4409a(6) =4909a(7) =4999a(8) =9049a(9) =9949a(10) =40009a(11) =40099a(12) =40499a(13) =40949a(14) =44449a(15) =44909a(16) =49009a(17) =49409a(18) =49499a(19) =49999a(20) =90499a(21) =94009a(22) =94049a(23) =94099a(24) =94949a(25) =94999a(26) =99409a(27) =400009a(28) =400409a(29) =400949