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 A137111 Numbers k such that k and k^2 use only the digits 2, 5, 6, 7 and 8. 1

%I #9 Apr 12 2024 09:51:27

%S 5,25,26,75,76,85,275,525,526,725,765,766,826,875,2585,2785,2875,5275,

%T 7525,7665,7666,8525,8675,8765,8865,8875,26875,27525,27725,28675,

%U 28785,52525,52785,72576,72585,76526,76585,76665,76666,76725,82875,88785,228665,256266,256275,276725,278725,278865,287725,287865,526525,526865,527525,725725,752785

%N Numbers k such that k and k^2 use only the digits 2, 5, 6, 7 and 8.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A137111/b137111.txt">Table of n, a(n) for n = 1..844</a>

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

%e 875686752587525^2 = 766827288657285222282785625625.

%t With[{c={2,5,6,7,8}},Select[Flatten[Table[FromDigits/@Tuples[c,n],{n,6}]],SubsetQ[ c,IntegerDigits[#^2]]&]] (* _Harvey P. Dale_, Mar 14 2023 *)

%K base,nonn

%O 1,1

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

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Last modified August 15 08:18 EDT 2024. Contains 375173 sequences. (Running on oeis4.)