login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A299116 The number of sparse union-closed sets. That is, the number of union-closed sets on n elements containing the empty set and the universe, such that in average each set (not counting the empty set) has at most n/2 elements. 0
0, 0, 0, 2, 27, 3133, 5777931 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

If there is a counterexample to the union-closed set conjecture, it is a sparse union-closed set.

LINKS

Table of n, a(n) for n=1..7.

G. Brinkmann and R. Deklerck, Generation of Union-Closed Sets and Moore Families, arXiv:1701.03751 [math.CO], 2017.

G. Brinkmann and R. Deklerck, Generation of Union-Closed Sets and Moore Families, Journal of Integer Sequences, Vol.21 (2018), Article 18.1.7.

CROSSREFS

Cf. A108798, A102894, A193674, A102896.

Sequence in context: A113094 A327128 A320669 * A076113 A182335 A056013

Adjacent sequences:  A299113 A299114 A299115 * A299117 A299118 A299119

KEYWORD

nonn,more

AUTHOR

Gunnar Brinkmann, Feb 05 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 27 10:44 EDT 2021. Contains 346304 sequences. (Running on oeis4.)