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 A137028 #9 Apr 12 2024 09:51:27
%S A137028 1,38,88,1188,4141,8878,11478,18471,33878,183878,844878,887771,
%T A137028 1347141,3381378,33883878,43344878,88811471,177317438,178374141,
%U A137028 333374141,338841141,344743878,844877141,887377438,3334348188,3441183188,8817473471,11483831378,13347183878,13371137378,13484747378,17713783188,17744811471
%N A137028 Numbers k such that k and k^2 use only the digits 1, 3, 4, 7 and 8.
%C A137028 Generated with DrScheme.
%H A137028 Jonathan Wellons, <a href="/A137028/b137028.txt">Table of n, a(n) for n = 1..112</a>
%H A137028 J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]
%e A137028 344787487347378^2 = 118878411431318344438843474884.
%t A137028 Module[{c={1,3,4,7,8}},Table[Select[FromDigits/@Tuples[c,n],SubsetQ[c,IntegerDigits[#^2]]&],{n,11}]]//Flatten (* _Harvey P. Dale_, Feb 22 2024 *)
%K A137028 base,nonn
%O A137028 1,2
%A A137028 Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008