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A118077
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Number of edges in the representation of all linear extensions of the inclusion ordering on P({1,...,n}) as distributive lattice contained in P(P({1,...,n})).
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1
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OFFSET
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0,2
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COMMENTS
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The numbers of vertices are the Dedekind numbers (A000372) and A046873 is the total number of linear extensions.
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LINKS
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FORMULA
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EXAMPLE
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a(2) = 6 as the lattice is { {}, { {} }, { {}, {1} }, { {}, {2} }, { {}, {1}, {2}}, { {}, {1}, {2}, {1, 2} } }.
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PROG
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(Python) # using an inference method for computing the set of linear extensions of arbitrary posets.
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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