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 A087536 #14 Sep 20 2024 23:54:32
%S A087536 67,67766767,76767667,6666767777,6667677677,6667776767,6667777667,
%T A087536 6676766777,6676767677,6676776677,6677666777,6677667767,6677676767,
%U A087536 6766677767,6766776677,6767667677,6767677667,6776766677,6776766767,6776767667,6777667667,7666677677,7666767677,7667676677
%N A087536 Primes consisting only of digits 6 and 7 occurring with equal frequency.
%C A087536 There are 18 digit pairs which can produce such primes. (1,0),(1,3),(1,4),(1,6),(1,7),(1,9),(2,3),(2,9),(3,4),(3,5),(3,7),(3,8),(4,7),(4,9),(5,9),(6,7),(7,9),(8,9).
%H A087536 Andrew Howroyd, <a href="/A087536/b087536.txt">Table of n, a(n) for n = 1..5129</a> (first 5001 terms from Harvey P. Dale)
%t A087536 Sort[Flatten[Table[Select[FromDigits/@Permutations[PadRight[{},2n,{6,7}]],PrimeQ],{n,5}]]] (* _Harvey P. Dale_, Dec 03 2012 *)
%o A087536 (PARI) \\ Needs B() from A087510.
%o A087536 concat(vector(6,k,B(k,6,7,isprime))) \\ _Andrew Howroyd_, Sep 20 2024
%Y A087536 Cf. A087510, A087511, A087535.
%K A087536 base,nonn
%O A087536 1,1
%A A087536 _Amarnath Murthy_ and _Paul D. Hanna_, Sep 12 2003
%E A087536 Edited by _Charles R Greathouse IV_, Oct 28 2009
%E A087536 Offset changed by _Andrew Howroyd_, Sep 20 2024