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 A137007 #24 May 10 2024 08:51:35
%S A137007 1,5,11,15,715
%N A137007 Numbers k such that k and k^2 use only the digits 1, 2, 5 and 7.
%C A137007 Generated with DrScheme.
%C A137007 No additional terms up to and including 7,777,777,777. - _Harvey P. Dale_, Sep 04 2018
%C A137007 No additional terms up to 10^26. - _L. Joris Perrenet_, Jul 02 2020
%C A137007 No additional terms up to 10^39. - _Michael S. Branicky_, Apr 12 2024
%H A137007 Jonathan Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]
%e A137007 715^2 = 511225.
%t A137007 Module[{nn=10,c={1,2,5,7}},Select[Flatten[Table[FromDigits/@Tuples[c,n],{n,nn}]],SubsetQ[c,IntegerDigits[#^2]]&]] (* _Harvey P. Dale_, Sep 04 2018 *)
%K A137007 base,nonn,more
%O A137007 1,2
%A A137007 Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008