Primes consisting only of digits 1 and 7 occurring with equal frequency.

Terms

a(0) =17a(1) =71a(2) =11171777a(3) =11177717a(4) =17111777a(5) =17171177a(6) =17171771a(7) =17177117a(8) =17711717a(9) =17717171a(10) =71117177a(11) =71171717a(12) =71717117a(13) =77111717a(14) =77711171a(15) =1111717777a(16) =1117117777a(17) =1117177177a(18) =1117771177a(19) =1117771717a(20) =1177117177a(21) =1177177711a(22) =1177711177a(23) =1177717171a(24) =1177717711