%I #9 Jul 30 2024 18:07:29
%S 0,2,20,22,200,202,220,2000,2002,2020,2022,2200,2202,20000,20002,
%T 20020,20022,20200,20220,22000,22002,22020,200000,200002,200020,
%U 200022,200200,200202,200220,202000,202002,202200,220000,220002,220020,220200,2000000,2000002,2000020,2000022,2000200,2000202,2000220,2002000,2002020,2002200,2020000
%N Numbers k such that k and k^2 use only the digits 0, 2, 4 and 8.
%C Generated with DrScheme.
%H Jonathan Wellons, <a href="/A136908/b136908.txt">Table of n, a(n) for n = 1..1389</a>
%H J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]
%e 202002000200202^2 = 40804808084882408848080840804.
%t With[{c={0,2,4,8}},Select[FromDigits/@Tuples[c,7],SubsetQ[c,IntegerDigits[#^2]]&]] (* _Harvey P. Dale_, Jul 30 2024 *)
%K base,nonn
%O 1,2
%A Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008