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Numbers k such that k and k^2 use only the digits 2, 3, 4, 6 and 9.
1

%I #10 Apr 12 2024 09:51:27

%S 2,3,6,63,264,632,964,2236,4932,4942,4943,22236,22292,26394,26443,

%T 49332,49342,49423,49693,49694,62963,66292,66332,222923,494236,494262,

%U 494392,494462,496632,499332,499342,499392,499423,499432,626394,996693,996962,2224694,2496643,2632343,2632344,2639364,4946662,4993332,4993923,4994236

%N Numbers k such that k and k^2 use only the digits 2, 3, 4, 6 and 9.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A137073/b137073.txt">Table of n, a(n) for n = 1..644</a>

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

%e 969362934942323^2 = 939664499639994332999336636329.

%t With[{c={2,3,4,6,9}},Table[Select[FromDigits/@Tuples[c,n],SubsetQ[c, IntegerDigits[ #^2]]&],{n,7}]]//Flatten (* _Harvey P. Dale_, May 15 2017 *)

%K base,nonn

%O 1,1

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