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A063582
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Smallest k such that 4^k has exactly n 7's in its decimal representation.
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1
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1, 10, 15, 12, 23, 60, 58, 76, 83, 85, 114, 130, 151, 141, 180, 107, 174, 190, 249, 187, 248, 220, 212, 269, 287, 297, 237, 316, 327, 370, 405, 383, 416, 313, 424, 412, 390, 483, 512, 496, 479, 502, 596, 578, 626, 581, 612, 593, 446, 587, 600
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OFFSET
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0,2
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LINKS
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MATHEMATICA
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a = {}; Do[k = 1; While[ Count[ IntegerDigits[4^k], 7] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
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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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EXTENSIONS
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STATUS
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approved
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