Primes having only {5, 6, 7} as digits.

Terms

a(0) =5a(1) =7a(2) =67a(3) =557a(4) =577a(5) =677a(6) =757a(7) =5557a(8) =5657a(9) =6577a(10) =7577a(11) =7757a(12) =55667a(13) =56767a(14) =57557a(15) =57667a(16) =65557a(17) =65657a(18) =65677a(19) =65777a(20) =67567a(21) =67577a(22) =67757a(23) =67777a(24) =75557a(25) =75577a(26) =75767a(27) =76667a(28) =76757a(29) =76777