A358390 The number of maximal antichains in the Kreweras lattice of non-crossing set partitions of an n-element set.

1, 2, 3, 25, 2117, 22581637702

Offset

1,2

Comments

Also similar to the number of maximal antichains in the lattice of set partitions or in the Boolean lattice.

Links

Table of n, a(n) for n=1..6.

Dmitry I. Ignatov, Supporting iPython code and input files for counting (maximal) antichains of the non-crossing set partition lattice up to n=5, Github repository.

G. Kreweras, Sur les partitions non croisées d'un cycle, Discrete Math., 4(1972), 333-350.

Crossrefs

Cf. A302250 (number of antichains in the lattice of set partitions).

Cf. A326358 (number of maximal antichains in the Boolean lattice).

Cf. A000108 (number of noncrossing partitions of a set of n elements)

Sequence in context: A109586 A127231 A060371 * A130975 A002748 A056004

Adjacent sequences: A358387 A358388 A358389 * A358391 A358392 A358393

Keyword

nonn,hard,more

Author

Dmitry I. Ignatov, Nov 13 2022

Status

approved