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A140317
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Smallest n-digit number divisible by n^2.
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2
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1, 12, 108, 1008, 10000, 100008, 1000041, 10000000, 100000008, 1000000000, 10000000109, 100000000080, 1000000000116, 10000000000144, 100000000000125, 1000000000000000, 10000000000000152, 100000000000000008
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(7) = 1000041 because 1000041 has 7 digits, 1000041/49 = 20409 = 3 * 6803 and no integer between 1000000 and 1000041 is divisible by 7^2 = 49.
a(9) = 100000008 because 100000008 has 9 digits, 100000008/81 = 1234568 = 23 * 154321 and no integer between 100000000 and 100000008 is divisible by 9^2 = 81.
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MAPLE
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MATHEMATICA
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snd[n_]:=Module[{c=n^2-PowerMod[10, n-1, n^2]}, If[Divisible[10^(n-1), n^2], 10^(n-1), 10^(n-1)+c]]; Array[snd, 20] (* Harvey P. Dale, Dec 14 2012 *)
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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