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A319721 Number of non-isomorphic antichains of multisets of weight n. 35
1, 1, 4, 8, 24, 50, 148, 349, 1014, 2717, 8114 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
In an antichain, no part is a proper submultiset of any other. The weight of an antichain is the sum of sizes of its parts. Weight is generally not the same as number of vertices.
LINKS
Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, Journal of Integer Sequences, Vol. 7 (2004).
EXAMPLE
Non-isomorphic representatives of the a(1) = 1 through a(3) = 8 antichains:
1: {{1}}
2: {{1,1}}
{{1,2}}
{{1},{1}}
{{1},{2}}
3: {{1,1,1}}
{{1,2,2}}
{{1,2,3}}
{{1},{2,2}}
{{1},{2,3}}
{{1},{1},{1}}
{{1},{2},{2}}
{{1},{2},{3}}
CROSSREFS
Sequence in context: A266821 A306484 A208901 * A115641 A153334 A332871
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Sep 26 2018
STATUS
approved

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Last modified May 22 06:48 EDT 2024. Contains 372743 sequences. (Running on oeis4.)