Primes having only {1, 6, 7} as digits.

Terms

a(0) =7a(1) =11a(2) =17a(3) =61a(4) =67a(5) =71a(6) =167a(7) =617a(8) =661a(9) =677a(10) =761a(11) =1117a(12) =1171a(13) =1667a(14) =1777a(15) =6661a(16) =6761a(17) =7177a(18) =7717a(19) =11117a(20) =11161a(21) =11171a(22) =11177a(23) =11617a(24) =11677a(25) =11717a(26) =11777a(27) =16111a(28) =16661a(29) =17117