

A306006


Number of nonisomorphic intersecting setsystems of weight n.


27




OFFSET

0,4


COMMENTS

An intersecting setsystem S is a finite set of finite nonempty sets (edges), any two of which have a nonempty intersection. The weight of S is the sum of cardinalities of its elements. Weight is generally not the same as number of vertices.


LINKS

Table of n, a(n) for n=0..9.


EXAMPLE

Nonisomorphic representatives of the a(6) = 10 setsystems:
{{1,2,3,4,5,6}}
{{5},{1,2,3,4,5}}
{{1,5},{2,3,4,5}}
{{3,4},{1,2,3,4}}
{{1,2,5},{3,4,5}}
{{1,3,4},{2,3,4}}
{{3},{2,3},{1,2,3}}
{{4},{1,4},{2,3,4}}
{{1,2},{1,3},{2,3}}
{{1,4},{2,4},{3,4}}


CROSSREFS

Cf. A007716, A034691, A048143, A049311, A116540, A283877, A293606, A293607, A304867, A305999, A305854A305857, A306005A306008.
Sequence in context: A118728 A062860 A024369 * A047011 A259393 A018163
Adjacent sequences: A306003 A306004 A306005 * A306007 A306008 A306009


KEYWORD

nonn,more


AUTHOR

Gus Wiseman, Jun 16 2018


STATUS

approved



