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

Author

Martin Rubey, Mar 30 2023

Keywords

• nonn
• hard
• more

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

• Wikipedia, Eulerian poset

Programs

Sage

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