OFFSET
0,4
COMMENTS
A blob is a connected antichain of finite sets that cannot be capped by a hypertree with more than one branch.
LINKS
Gus Wiseman, Every Clutter Is a Tree of Blobs, The Mathematica Journal, Vol. 19, 2017.
EXAMPLE
Non-isomorphic representatives of the a(4) = 10 blobs:
{{1,2,3,4}}
{{1,3,4},{2,3,4}}
{{1,3},{1,4},{2,3,4}}
{{1,2},{1,3,4},{2,3,4}}
{{1,2,4},{1,3,4},{2,3,4}}
{{1,2},{1,3},{2,4},{3,4}}
{{1,2},{1,3},{1,4},{2,3,4}}
{{1,3},{1,4},{2,3},{2,4},{3,4}}
{{1,2,3},{1,2,4},{1,3,4},{2,3,4}}
{{1,2},{1,3},{1,4},{2,3},{2,4},{3,4}}
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 24 2018
STATUS
approved