Primes having only {4, 6, 7, 8} as digits.

Terms

a(0) =7a(1) =47a(2) =67a(3) =467a(4) =487a(5) =647a(6) =677a(7) =787a(8) =877a(9) =887a(10) =4447a(11) =4787a(12) =4877a(13) =7477a(14) =7487a(15) =7687a(16) =7867a(17) =7877a(18) =8447a(19) =8467a(20) =8647a(21) =8677a(22) =8747a(23) =8867a(24) =8887a(25) =44647a(26) =44687a(27) =44777a(28) =44867a(29) =44887