Primes having only {4, 6, 9} as digits.

Terms

a(0) =449a(1) =499a(2) =4649a(3) =4969a(4) =4999a(5) =6449a(6) =6469a(7) =6949a(8) =9649a(9) =9949a(10) =44449a(11) =44699a(12) =46499a(13) =46649a(14) =49499a(15) =49669a(16) =49999a(17) =64499a(18) =64969a(19) =66449a(20) =66499a(21) =66949a(22) =69499a(23) =94649a(24) =94949a(25) =94999a(26) =96469a(27) =99469a(28) =444449a(29) =444469