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A051820
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Number of n-digit numbers with nonzero multiplicative digital root 9.
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1
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1, 4, 25, 180, 1640, 17678, 213761, 2572363, 28717151, 295374892, 2863710220, 27059835840, 257084859669, 2498594395926, 24825380748687, 249116120158421
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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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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# { i : 10^(n-1) < i < 10^n and A051802(i)=9 }
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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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