OFFSET
0,9
COMMENTS
A set system is a finite set of finite nonempty sets. It is intersecting if no two parts are disjoint. The weight of a set system 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(6) = 1 through a(9) = 8 set systems:
6: {{1,2},{1,3},{2,3}}
7: {{1,3},{1,4},{2,3,4}}
8: {{1,2},{1,3,4},{2,3,4}}
{{1,4},{1,5},{2,3,4,5}}
{{2,4},{1,2,5},{3,4,5}}
9: {{1,3},{1,4,5},{2,3,4,5}}
{{1,5},{1,6},{2,3,4,5,6}}
{{2,5},{1,2,6},{3,4,5,6}}
{{1,2,3},{2,4,5},{3,4,5}}
{{1,3,5},{2,3,6},{4,5,6}}
{{1,2},{1,3},{1,4},{2,3,4}}
{{1,2},{1,3},{2,3},{1,2,3}}
{{1,3},{1,4},{3,4},{2,3,4}}
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Sep 27 2018
STATUS
approved