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 A136865 #9 Apr 12 2024 09:51:26
%S A136865 0,1,7,10,70,97,100,107,700,701,970,997,1000,1007,1049,1070,1071,7000,
%T A136865 7001,7010,7071,9700,9701,9970,9997,10000,10007,10070,10097,10490,
%U A136865 10700,10710,14107,70000,70001,70010,70100,70107,70499,70710,97000,97001,97010,99700,99970,99997,100000,100007,100070,100097,100499,100700,100970,104900,107000
%N A136865 Numbers k such that k and k^2 use only the digits 0, 1, 4, 7 and 9.
%C A136865 Generated with DrScheme.
%H A136865 Jonathan Wellons, <a href="/A136865/b136865.txt">Table of n, a(n) for n = 1..1020</a>
%H A136865 J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]
%e A136865 4140170401071^2 = 17141010949904404997947041.
%t A136865 With[{c={0,1,4,7,9}},Select[FromDigits/@Tuples[c,6], SubsetQ[ c,IntegerDigits[ #^2]]&]] (* _Harvey P. Dale_, Aug 13 2020 *)
%K A136865 base,nonn
%O A136865 1,3
%A A136865 Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008