login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A319719 Number of non-isomorphic connected antichains of multisets of weight n. 23
1, 1, 3, 4, 10, 14, 48, 95, 305, 822, 2615 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

In an antichain, no part is a proper submultiset of any other. The weight of an antichain is the sum of sizes of its parts. Weight is generally not the same as number of vertices. Connected antichains are also called clutters.

LINKS

Table of n, a(n) for n=0..10.

Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, Journal of Integer Sequences, Vol. 7 (2004).

EXAMPLE

Non-isomorphic representatives of the a(1) = 1 through a(4) = 10 connected antichains:

1: {{1}}

2: {{1,1}}

   {{1,2}}

   {{1},{1}}

3: {{1,1,1}}

   {{1,2,2}}

   {{1,2,3}}

   {{1},{1},{1}}

4: {{1,1,1,1}}

   {{1,1,2,2}}

   {{1,2,2,2}}

   {{1,2,3,3}}

   {{1,2,3,4}}

   {{1,1},{1,1}}

   {{1,2},{1,2}}

   {{1,2},{2,2}}

   {{1,3},{2,3}}

   {{1},{1},{1},{1}}

CROSSREFS

Cf. A001055, A001970, A007716, A007718, A056156, A096827, A253249, A285573, A293994, A318099, A319557, A319616-A319646, A319721.

Sequence in context: A056516 A056517 A285042 * A048155 A242342 A204292

Adjacent sequences:  A319716 A319717 A319718 * A319720 A319721 A319722

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Sep 26 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 August 25 10:10 EDT 2019. Contains 326324 sequences. (Running on oeis4.)