login
A358391
The number of antichains in the Kreweras lattice of non-crossing set partitions of an n-element set.
1
2, 3, 10, 234, 2342196
OFFSET
1,1
COMMENTS
This is also the number of order ideals (down-sets) for this lattice.
Also similar to the number of antichains in the lattice of set partitions or in the Boolean lattice.
CROSSREFS
Cf. A000372 (number of antichains in the Boolean lattice).
Cf. A143673 (number of antichains in the lattice of Dyck paths).
Cf. A302250 (number of antichains in the lattice of set partitions).
Sequence in context: A162647 A368063 A364140 * A132536 A322067 A302250
KEYWORD
nonn,hard,more
AUTHOR
Dmitry I. Ignatov, Nov 13 2022
STATUS
approved