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A176767
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Smallest power of 7 whose decimal expansion contains n.
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1
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2401, 1, 2401, 343, 49, 823543, 16807, 7, 16807, 49, 96889010407, 117649, 13841287201, 13841287201, 11398895185373143, 4747561509943, 16807, 117649, 11398895185373143, 1977326743, 13841287201, 3909821048582988049
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OFFSET
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0,1
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COMMENTS
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This is to 7 as A176763 is to 3 and as A030001 is to 2.
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LINKS
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Table of n, a(n) for n=0..21.
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FORMULA
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a(n) = MIN{A000420(i) such that n in decimal representation is a substring of A000420(i)}.
a(n) = 7^A062524(n). - Michel Marcus, Sep 30 2014
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EXAMPLE
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a(1) = 1 because 7^0 = 1 has "1" as a substring (not a proper substring, though).
a(2) = 2401 because 7^4 = 2401 has "2" as a substring.
a(3) = 343 because 7^3 = 343 has "3" as a substring.
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CROSSREFS
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Cf. A000420, A030001, A176763, A176764-A176773.
Sequence in context: A235259 A321638 A005073 * A018865 A186488 A186487
Adjacent sequences: A176764 A176765 A176766 * A176768 A176769 A176770
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KEYWORD
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base,easy,nonn
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AUTHOR
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Jonathan Vos Post, Apr 25 2010
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EXTENSIONS
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More terms from Sean A. Irvine and Jon E. Schoenfield, May 05 2010
Extended to a(0) by M. F. Hasler, Oct 03 2014
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STATUS
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approved
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