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Search: id:A051459
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| A051459 |
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Number of orderings of the subsets of a set with n elements that are compatible with the subsets' sizes; i.e. if A, B are two subsets with A<=B then Card(A)<=Card(B). |
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1
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| 1, 2, 36, 414720, 189621927936000000, 2156695499113014719143826715127578624000000000000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(7) has 127 digits and too large to include in sequence. - Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 22 2003
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FORMULA
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a(n) = C(n, 0)! * C(n, 1)! * C(n, 2)! * ... * C(n, n)! = A000722(n) / A022914(n).
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CROSSREFS
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Cf. A000722, A022914, A001142.
Sequence in context: A060739 A134366 A127234 this_sequence A073581 A078081 A077772
Adjacent sequences: A051456 A051457 A051458 this_sequence A051460 A051461 A051462
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KEYWORD
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nonn
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AUTHOR
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Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 15 2003
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EXTENSIONS
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More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 22 2003
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