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A366705
Number of symmetry classes of partially ordered pattern classes defined by avoiding a size n poset.
0
1, 1, 2, 7, 64, 1068, 32651
OFFSET
0,3
LINKS
Christian Bean, Émile Nadeau, Jay Pantone, and Henning Ulfarsson, Permutations avoiding bipartite partially ordered patterns have a regular insertion encoding, The Electronic Journal of Combinatorics, Volume 31, Issue 3 (2024); arXiv preprint, arXiv:2312.07716 [math.CO], 2023.
Alice L. L. Gao and Sergey Kitaev, On partially ordered patterns of length 4 and 5 in permutations, arXiv:1903.08946 [math.CO], 2019.
Alice L. L. Gao and Sergey Kitaev, On partially ordered patterns of length 4 and 5 in permutations, The Electronic Journal of Combinatorics 26(3) (2019), P3.26.
EXAMPLE
There are three labeled posets with 2 elements. The two chains generate symmetrically equivalent permutation classes, Av(12) and Av(21), while the third generates Av(12, 21) which is not equivalent to these. Therefore a(2) = 2.
CROSSREFS
Cf. A001035.
Sequence in context: A006506 A346781 A011821 * A117263 A046855 A179043
KEYWORD
nonn,more
AUTHOR
Jay Pantone, Oct 17 2023
STATUS
approved