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Numbers n such that n and the square of n use only the digits 3, 5, 6, 7 and 8.
1

%I #6 Apr 12 2024 09:51:27

%S 6,76,766,876,7666,8566,8756,8876,57756,76576,76666,85666,753576,

%T 766576,766666,856666,7587856,7666576,7666666,8566666,8576576,8765766,

%U 75336356,76666576,76666666,85666666,87558876,88536356,577558376,577566756,577653576,758733376,765883566,766666576,766666666,767383566,856666666,857768376

%N Numbers n such that n and the square of n use only the digits 3, 5, 6, 7 and 8.

%C Generated with DrScheme

%H Jonathan Wellons, <a href="/A137132/b137132.txt">Table of n, a(n) for n=1..122</a>

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

%e 765738688383876^2 = 586355738887858753336736783376

%t With[{c={3,5,6,7,8}},Select[FromDigits/@Flatten[Table[Tuples[c,n],{n,9}],1],SubsetQ[c,IntegerDigits[#^2]]&]] (* _Harvey P. Dale_, Feb 19 2018 *)

%K base,nonn

%O 1,1

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