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 A087512 #14 Sep 21 2024 13:24:19
%S A087512 41,14441411,41414411,44114141,1144141441,1144144411,1144441141,
%T A087512 1411414441,1441411441,1441444111,1444114141,4111144441,4111444411,
%U A087512 4114414141,4141141441,4141144141,4144111441,4411114441,4411144141,4411414411,4414141141,4414441111
%N A087512 Primes consisting only of digits 1 and 4 occurring with equal frequency.
%C A087512 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 A087512 Andrew Howroyd, <a href="/A087512/b087512.txt">Table of n, a(n) for n = 1..5319</a> (first 5001 terms from Harvey P. Dale)
%t A087512 Union[Flatten[Table[Select[FromDigits/@Permutations[Flatten[Table[{1,4},{n}]]],PrimeQ],{n,5}]]] (* _Harvey P. Dale_, Nov 21 2014 *)
%o A087512 (PARI) \\ Needs B() from A087510.
%o A087512 concat(vector(6,k,B(k,1,4,isprime))) \\ _Andrew Howroyd_, Sep 21 2024
%Y A087512 Cf. A087510, A087511, A087513.
%K A087512 base,nonn
%O A087512 1,1
%A A087512 _Paul D. Hanna_ and _Amarnath Murthy_, Sep 11 2003
%E A087512 More terms from _Harvey P. Dale_, Nov 21 2014
%E A087512 Offset changed by _Andrew Howroyd_, Sep 21 2024