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Numbers k such that k and k^2 use only the digits 1, 2, 5, 7 and 8.
1

%I #7 Apr 12 2024 09:51:27

%S 1,5,11,15,85,285,715,1585,2285,8711,28511,52515,52715,72285,151285,

%T 228511,285515,722211,852715,878511,2858711,2878511,7182285,7182515,

%U 7271285,8785711,8877811,8881585,15878511,28551285,71782715,75582585,111887511,125585515,277881585,278852515,287275515,727157285,758785711,882185515,887285515

%N Numbers k such that k and k^2 use only the digits 1, 2, 5, 7 and 8.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A137008/b137008.txt">Table of n, a(n) for n = 1..158</a>

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

%e 275182172182585^2 = 75725227887125857782577282225.

%K base,nonn

%O 1,2

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