A361921 The number of unlabeled bounded Eulerian posets with n elements.

0, 1, 1, 0, 1, 0, 1, 0, 2, 0, 5, 0, 11

Offset

0,9

Comments

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.

Links

Table of n, a(n) for n=0..12.

Wikipedia, Eulerian poset

Prog

(Sage) sum(1 for P in posets(n-2) if (Q := P.with_bounds()).is_graded() and Q.is_eulerian())

Crossrefs

Sequence in context: A242683 A242682 A281731 * A245928 A242839 A105523

Adjacent sequences: A361918 A361919 A361920 * A361922 A361923 A361924

Keyword

nonn,hard,more

Author

Martin Rubey, Mar 30 2023

Status

approved