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A137117
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Numbers k such that k and k^2 use only the digits 2, 5, 7 and 9.
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1
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OFFSET
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1,1
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COMMENTS
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Generated with DrScheme.
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LINKS
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EXAMPLE
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27797977^2 = 772727525292529.
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MATHEMATICA
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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 *)
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PROG
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
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STATUS
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approved
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