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A222819
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a(n) = number of nontrivial reverse multipliers for base n.
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5
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0, 1, 1, 2, 2, 2, 4, 3, 2, 5, 4, 3, 6, 6, 3, 7, 5, 7, 7, 6, 5, 10, 10, 5, 7, 8, 5, 12, 11, 9, 12, 5, 8, 13, 9, 8, 12, 16, 8, 14, 11, 12, 16, 12, 10, 19, 15, 11, 11, 9, 10, 19, 18, 17, 18, 13, 9, 23, 14, 15, 21, 19, 14, 19, 12, 18, 16, 19, 17, 26, 17, 11, 20, 16, 15, 21, 13, 26, 24, 13
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OFFSET
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2,4
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COMMENTS
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If there is a number m such that the reversal of m in base n is c times m, then c is called a reverse multiplier for n. For example, 2 is a reverse multiplier for base n=5, since 8 (base 10) = 13 (base 5), and 2*8 = 16 (base 10) = 31 (base 5).
The trivial reverse multiplier 1 is excluded.
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LINKS
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CROSSREFS
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See A214927 for other cross-references.
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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