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A046873
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Number of total orders extending inclusion on P({1,...,n}).
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2
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OFFSET
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0,3
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COMMENTS
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Trivial upper bound: a(n) <= (2^n)!.
Number of linear extensions of the Boolean lattice 2^n. - Mitch Harris, Dec 27 2005
The number of vertices in the representation of all linear extensions in a distributive lattice are the Dedekind numbers (A000372) and the number of edges constitutes A118077. - Oliver Wienand, Apr 11 2006
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LINKS
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EXAMPLE
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a(2)=2 because either {}<{0}<{1}<{0,1} or {}<{1}<{0}<{0,1}.
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CROSSREFS
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KEYWORD
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nonn,nice
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AUTHOR
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EXTENSIONS
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a(5) from Oliver Wienand, Apr 11 2006, using Python and an inference method for computing the set of linear extensions of arbitrary posets. Using the same method on a compute server generated a(6) on Dec 05 2010.
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STATUS
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approved
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