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A137106
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Numbers k such that k and k^2 use only the digits 2, 4, 7 and 8.
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0
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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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2878^2 = 8282884.
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MATHEMATICA
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oksQ[n_]:=Module[{idn2=Union[IntegerDigits[n^2]]}, And@@Table[MemberQ[{2, 4, 7, 8}, idn2[[i]]], {i, Length[idn2]}]]; Select[FromDigits/@Flatten[ Table[ Tuples[ {2, 4, 7, 8}, n], {n, 9}], 1], oksQ] (* Harvey P. Dale, Dec 15 2011 *)
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CROSSREFS
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KEYWORD
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base,nonn,more
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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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