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A137101
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Numbers k such that k and k^2 use only the digits 2, 4, 6, 7 and 8.
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1
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2, 8, 22, 26, 28, 68, 82, 88, 262, 278, 472, 474, 478, 668, 826, 2622, 2762, 2878, 4762, 6668, 8762, 8768, 8822, 8874, 26878, 27826, 28678, 66668, 66878, 68474, 82878, 86478, 87662, 88474, 666668, 666878, 684674, 687668, 822662, 2624478, 2724472, 2768474, 2867878, 2878626, 6666668, 6666878, 6684674, 6842826, 6886674, 8226474, 8274472
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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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876862462862762^2 = 768887778777748667624446268644.
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MATHEMATICA
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With[{c={2, 4, 6, 7, 8}}, Flatten[Table[Select[FromDigits/@Tuples[c, n], SubsetQ[ c, IntegerDigits[#^2]]&], {n, 7}]]] (* Harvey P. Dale, Dec 20 2014 *)
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CROSSREFS
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KEYWORD
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base,nonn,changed
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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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