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 A136927 #9 Apr 12 2024 09:51:26
%S A136927 0,6,60,66,600,656,660,666,6000,6560,6600,6660,6666,60000,63566,65600,
%T A136927 66000,66600,66660,66666,600000,603656,604434,635660,656000,660000,
%U A136927 660656,666000,666600,666660,666666,6000000,6036560,6044340,6356600,6560000,6600000,6606560,6660000,6666000,6666600,6666660,6666666,60000000,60054434,60365600
%N A136927 Numbers k such that k and k^2 use only the digits 0, 3, 4, 5 and 6.
%C A136927 Generated with DrScheme.
%C A136927 See also A058429-A058430. - _M. F. Hasler_, Jan 24 2008
%H A136927 Jonathan Wellons, <a href="/A136927/b136927.txt">Table of n, a(n) for n = 1..495</a>
%H A136927 J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]
%e A136927 665605465350506^2 = 443030635504463643353434456036.
%t A136927 With[{c={0,3,4,5,6},nn=8},Select[FromDigits/@Tuples[c,nn],SubsetQ[ c,IntegerDigits[ #^2]]&]] (* _Harvey P. Dale_, Apr 27 2022 *)
%K A136927 base,nonn
%O A136927 1,2
%A A136927 Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008