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Numbers k such that k and k^2 use only the digits 2, 3, 4, 7 and 9.
1

%I #8 Apr 12 2024 09:51:27

%S 2,3,7,27,223,473,4943,49777,222327,273393,477277,499423,499473,

%T 973393,2733943,4932923,4993443,4994777,4997927,49342927,49924277,

%U 49972927,49993443,49994223,49994777,97339223,492942927,494342927,497332327,497794473,497993923,499293443,499932923,499947327,499972927,499979277,499979327

%N Numbers k such that k and k^2 use only the digits 2, 3, 4, 7 and 9.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A137075/b137075.txt">Table of n, a(n) for n = 1..200</a>

%H J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]

%e 497242372972927^2 = 247249977479747443472274947329.

%K base,nonn

%O 1,1

%A Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008