

A048143


Number of labeled connected simplicial complexes with n nodes.


142




OFFSET

0,4


COMMENTS

Also number of connected antichains on a labeled nset.


LINKS

Table of n, a(n) for n=0..8.
Patrick De Causmaecker, Stefan De Wannemacker, On the number of antichains of sets in a finite universe, arXiv:1407.4288 [math.CO], 2014.
Greg Huber, Letters to N. J. A. Sloane, May 1983 [Annotated, corrected, scanned copy]
Gus Wiseman, Every Clutter Is a Tree of Blobs, The Mathematica Journal, Vol. 19, 2017.
Gus Wiseman, Sequences enumerating clutters, antichains, hypertrees, and hyperforests, organized by labeling, spanning, and allowance of singletons.


EXAMPLE

For n=3 we could have 2 edges (in 3 ways), 3 edges (1 way), or 3 edges and a triangle (1 way), so a(3)=5.
a(5) = 1+75+645+1655+2005+1345+485+115+20+2 = 6348.


CROSSREFS

Cf. A094033, A094034, A094035, A094036, A094037.
Cf. A000666, A006126, A030019, A054921, A120338, A275307, A285572.
Sequence in context: A156720 A288163 A268880 * A216420 A137083 A198586
Adjacent sequences: A048140 A048141 A048142 * A048144 A048145 A048146


KEYWORD

nonn,nice,more


AUTHOR

Greg Huber, May 12 1983


EXTENSIONS

More terms from Vladeta Jovovic, Jun 17 2006
Entry revised by N. J. A. Sloane, Jul 27 2006


STATUS

approved



