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A305028 Number of unlabeled blobs spanning n vertices without singleton edges. 4

%I

%S 1,0,1,2,10,128

%N Number of unlabeled blobs spanning n vertices without singleton edges.

%C A blob is a connected antichain of finite sets that cannot be capped by a hypertree with more than one branch.

%H Gus Wiseman, <a href="http://www.mathematica-journal.com/2017/12/every-clutter-is-a-tree-of-blobs/">Every Clutter Is a Tree of Blobs</a>, The Mathematica Journal, Vol. 19, 2017.

%e Non-isomorphic representatives of the a(4) = 10 blobs:

%e {{1,2,3,4}}

%e {{1,3,4},{2,3,4}}

%e {{1,3},{1,4},{2,3,4}}

%e {{1,2},{1,3,4},{2,3,4}}

%e {{1,2,4},{1,3,4},{2,3,4}}

%e {{1,2},{1,3},{2,4},{3,4}}

%e {{1,2},{1,3},{1,4},{2,3,4}}

%e {{1,3},{1,4},{2,3},{2,4},{3,4}}

%e {{1,2,3},{1,2,4},{1,3,4},{2,3,4}}

%e {{1,2},{1,3},{1,4},{2,3},{2,4},{3,4}}

%Y Cf. A030019, A035053, A048143, A054921, A134957, A144959, A275307, A286520, A293607, A304118, A304717, A304867.

%K nonn

%O 0,4

%A _Gus Wiseman_, May 24 2018

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Last modified April 16 17:01 EDT 2021. Contains 343050 sequences. (Running on oeis4.)