This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A257937 #17 Jun 25 2022 17:07:57
%S A257937 1111151,1111181,1111211,1111711,1114111,1117111,1171111,2999999,
%T A257937 3233333,3331333,3333133,3333233,3333313,3333331,3333373,3333383,
%U A257937 3333433,3337333,3353333,3433333,3733333,4999999,7477777,7577777,7727777,7772777,7774777,7777727,7778777,7877777,9899999,9929999,9999299,9999929,9999991
%N A257937 Primes p such that one digit appears exactly six times together with a single different digit.
%C A257937 All the terms are congruent to 1 or 2 (mod 3).
%C A257937 In no term does the digit 0, 2, 4, 5, 6, or 8 appear six times.
%H A257937 K. D. Bajpai, <a href="/A257937/b257937.txt">Table of n, a(n) for n = 1..35</a>
%e A257937 a(1) = 1111151 has exactly six 1's together with a single digit 5.
%e A257937 a(8) = 2999999 has exactly six 9's together with a single digit 2.
%p A257937 sort(select(isprime, [seq(seq(seq(d*1111111 + (a-d)*10^k, k=0..6), a={$1..9} minus {d}),d=1..9)])); # _Robert Israel_, Jul 13 2015
%t A257937 kQ[n_]:= Module[{d=Select[DigitCount[n], # > 0 &]},Length[d] == 2 && Min[d] == 1 && Max[d] == 6]; Select[Table[Prime[n], {n, 1000000}], kQ]
%t A257937 Select[Prime[Range[80000, 400000]], MemberQ[DigitCount[#], 6] &] (* _Vincenzo Librandi_, Jul 14 2015 *)
%Y A257937 Cf. A105992, A161786, A161796.
%K A257937 nonn,base,fini,full
%O A257937 1,1
%A A257937 _K. D. Bajpai_, Jul 13 2015