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 A137139 #8 May 10 2024 11:28:16 %S A137139 74,76,74476,74474476 %N A137139 Numbers k such that k and k^2 use only the digits 4, 5, 6 and 7. %C A137139 Generated with DrScheme. %H A137139 Jonathan Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived] %e A137139 74474476^2 = 5546447575474576. %K A137139 base,nonn,more %O A137139 1,1 %A A137139 Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008