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A361921
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The number of unlabeled bounded Eulerian posets with n elements.
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0
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0, 1, 1, 0, 1, 0, 1, 0, 2, 0, 5, 0, 11
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OFFSET
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0,9
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COMMENTS
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A graded partially ordered set is Eulerian if every nontrivial interval has the same number of elements of even rank as of odd rank. It is bounded if it has a unique maximal and a unique minimal element.
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LINKS
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PROG
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(Sage) sum(1 for P in posets(n-2) if (Q := P.with_bounds()).is_graded() and Q.is_eulerian())
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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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STATUS
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approved
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