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A059436
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Smallest number whose set of divisors contains each digit 0-9 at least n times.
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4
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108, 540, 1140, 1890, 3420, 5460, 7980, 11760, 16380, 29700, 23520, 23760, 44460, 38220, 51480, 47880, 41580, 97020, 87780, 71820, 98280, 103740, 83160, 154440, 124740, 143640, 207480, 166320, 278460, 382200, 263340, 249480, 311220, 335160
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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Robert G. Wilson v, Table of n, a(n) for n = 1..402 .
Erich Friedman, What's Special About This Number? (See entry 7980.)
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EXAMPLE
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The divisors of 540 are 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 27, 30, 36, 45, 54, 60, 90, 108, 135, 180, 270, 540 and every digit appears at least twice in this list.
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MATHEMATICA
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f[n_] := Block[{s = Transpose@ Tally[ Sort[ Flatten[ IntegerDigits@# & /@ Divisors@ n]]]}, If[First@s == {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, Min@ Last@s, 0]]; t = Table[0, {50}]; k = 6; While[k < 400000, a = f@k; If[ t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k += 6]; t [From Robert G. Wilson v, Jul 31 2010]
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PROG
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(Haskell)
import Data.List (group, sort)
a059436 n = head [x | x <- [1..],
let dds = map length $ group $ sort $ concatMap show $ a027750_row x,
minimum dds == n, length dds == 10]
-- Reinhard Zumkeller, Feb 04 2012
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CROSSREFS
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Cf. A027750; subsequence of A095050, A095048.
Sequence in context: A202428 A224526 A063880 * A160919 A129027 A204276
Adjacent sequences: A059433 A059434 A059435 * A059437 A059438 A059439
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KEYWORD
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base,nonn,nice
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AUTHOR
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Erich Friedman, Feb 01 2001
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EXTENSIONS
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More terms from David W. Wilson, Aug 31 2001
Offset corrected by R. J. Mathar, Jun 02 2010
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STATUS
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approved
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