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A051812
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Number of n-digit numbers with nonzero multiplicative digital root 1.
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1
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1, 5, 24, 243, 3048, 35224, 374890, 3766188, 36537927, 348892847, 3315037530, 31399344551, 295789894509, 2769886220702, 25882768895688, 243033400452156
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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Not counting zero as a one-digit number.
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REFERENCES
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William Mayne, sci.math, Jun 15 1991
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LINKS
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FORMULA
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a(n) = # { i : 10^(n-1) < i < 10^n and A051802(i)=1 }.
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CROSSREFS
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KEYWORD
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nonn,base,hard
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AUTHOR
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STATUS
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approved
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