# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a305028 Showing 1-1 of 1 %I A305028 #6 May 24 2018 13:23:17 %S A305028 1,0,1,2,10,128 %N A305028 Number of unlabeled blobs spanning n vertices without singleton edges. %C A305028 A blob is a connected antichain of finite sets that cannot be capped by a hypertree with more than one branch. %H A305028 Gus Wiseman, Every Clutter Is a Tree of Blobs, The Mathematica Journal, Vol. 19, 2017. %e A305028 Non-isomorphic representatives of the a(4) = 10 blobs: %e A305028 {{1,2,3,4}} %e A305028 {{1,3,4},{2,3,4}} %e A305028 {{1,3},{1,4},{2,3,4}} %e A305028 {{1,2},{1,3,4},{2,3,4}} %e A305028 {{1,2,4},{1,3,4},{2,3,4}} %e A305028 {{1,2},{1,3},{2,4},{3,4}} %e A305028 {{1,2},{1,3},{1,4},{2,3,4}} %e A305028 {{1,3},{1,4},{2,3},{2,4},{3,4}} %e A305028 {{1,2,3},{1,2,4},{1,3,4},{2,3,4}} %e A305028 {{1,2},{1,3},{1,4},{2,3},{2,4},{3,4}} %Y A305028 Cf. A030019, A035053, A048143, A054921, A134957, A144959, A275307, A286520, A293607, A304118, A304717, A304867. %K A305028 nonn %O A305028 0,4 %A A305028 _Gus Wiseman_, May 24 2018 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE