OFFSET
0,5
COMMENTS
The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices.
EXAMPLE
Non-isomorphic representatives of the a(2) = 1 through a(6) = 11 antichains:
{{1,2}} {{1,2,3}} {{1,2,3,4}} {{1,2,3,4,5}} {{1,2,3,4,5,6}}
{{1,2},{3,4}} {{1,2},{3,4,5}} {{1,2},{3,4,5,6}}
{{1,3},{2,3}} {{1,4},{2,3,4}} {{1,2,3},{4,5,6}}
{{1,2,5},{3,4,5}}
{{1,3,4},{2,3,4}}
{{1,5},{2,3,4,5}}
{{1,2},{1,3},{2,3}}
{{1,2},{3,4},{5,6}}
{{1,2},{3,5},{4,5}}
{{1,3},{2,4},{3,4}}
{{1,4},{2,4},{3,4}}
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Nov 16 2018
STATUS
approved