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%I #14 Apr 12 2024 18:06:35
%S 5,27,77,527,7227,27797977
%N Numbers k such that k and k^2 use only the digits 2, 5, 7 and 9.
%C Generated with DrScheme.
%C No further terms up to 10^12. - _Harvey P. Dale_, Oct 02 2017
%C No further terms up to 10^38. - _Michael S. Branicky_, May 27 2021
%H Jonathan Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived].
%e 27797977^2 = 772727525292529.
%t With[{c={2,5,7,9}},Table[Select[FromDigits/@Tuples[c,n],SubsetQ[c, IntegerDigits[ #^2]]&],{n,8}]]//Flatten (* _Harvey P. Dale_, Oct 02 2017 *)
%o (Python) # uses auptod in A137110
%o print(auptod(16, only="2579")) # _Michael S. Branicky_, May 27 2021
%Y Cf. A137110, A137116.
%K base,nonn,changed
%O 1,1
%A Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
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