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A113599
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Least n-digit multiple of n whose digit permutations yield at least n distinct multiples of n, or 0 if no such number exists.
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0
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1, 20, 102, 1004, 10005, 100002, 1000013, 10000008, 100000008, 1000000010, 10000000010, 100000000008, 1000000000012, 10000000000004, 100000000000005, 1000000000000016, 10000000000000016, 100000000000000008, 1000000000000000018
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OFFSET
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1,2
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COMMENTS
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Conjecture: No term is zero. The proof should be simple.
The conjecture is true: There are 9*10^(n-1) n-digit numbers, meaning at least floor(9*10^(n-1)/n) n-digit multiples of n. There are binomial(n+9, 9) multisets of n digits. Thus, by the pigeonhole principle, one of these multisets contains at least ceiling(floor(9*10^(n-1)/n)/binomial(n+9, 9)) multiples of n, and this number is at least n whenever n > 3. - James Rayman, Feb 14 2023
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LINKS
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EXAMPLE
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a(4) = 1004; the multiples of 4 arising as a digit permutation are 1004, 1040, 1400, 4100.
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CROSSREFS
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KEYWORD
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base,easy,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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