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Search: id:A061095
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| A061095 |
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Number of ways of dividing n labeled items into labeled boxes with an equal number of items in each box. |
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+0
4
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| 1, 3, 7, 31, 121, 831, 5041, 42911, 364561, 3742453, 39916801, 486891175, 6227020801, 87859375033, 1307843292757, 21004582611871, 355687428096001
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n) =Sum{d|n}[n!/(n/d)!^d].
E.g.f.: Sum_{k>0} x^k/(k!-x^k). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Oct 13 2003
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EXAMPLE
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a(6)=720+90+20+1=831 since 720 ways of evenly distributing six labeled items into six labeled boxes, 90 into three, 20 into two, and 1 into one.
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CROSSREFS
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Cf. A038041, A060538.
Adjacent sequences: A061092 A061093 A061094 this_sequence A061096 A061097 A061098
Sequence in context: A132153 A002357 A105765 this_sequence A103901 A089162 A016047
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KEYWORD
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nonn,nice,easy
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), May 29 2001
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