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A320800 Number of non-isomorphic multiset partitions of weight n in which both the multiset union of the parts and the multiset union of the dual parts are aperiodic. 9
1, 1, 1, 5, 14, 78, 157, 881, 2267, 9257, 28397 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

The latter condition is equivalent to the parts having relatively prime sizes.

A multiset is aperiodic if its multiplicities are relatively prime.

The dual of a multiset partition has, for each vertex, one part consisting of the indices (or positions) of the parts containing that vertex, counted with multiplicity. For example, the dual of {{1,2},{2,2}} is {{1},{1,2,2}}.

The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices.

LINKS

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

EXAMPLE

Non-isomorphic representatives of the a(1) = 1 through a(4) = 14 multiset partitions:

  {{1}}  {{1},{2}}  {{1},{2,2}}    {{1},{2,2,2}}

                    {{1},{2,3}}    {{1},{2,3,3}}

                    {{2},{1,2}}    {{1},{2,3,4}}

                    {{1},{2},{2}}  {{2},{1,2,2}}

                    {{1},{2},{3}}  {{3},{1,2,3}}

                                   {{1},{1},{2,3}}

                                   {{1},{2},{2,2}}

                                   {{1},{2},{3,3}}

                                   {{1},{2},{3,4}}

                                   {{1},{3},{2,3}}

                                   {{2},{2},{1,2}}

                                   {{1},{2},{2},{2}}

                                   {{1},{2},{3},{3}}

                                   {{1},{2},{3},{4}}

CROSSREFS

Cf. A000740, A000837, A007716, A007916, A100953, A301700, A303386, A303431, A303546, A303547, A316983, A320801-A320810.

Sequence in context: A305341 A316611 A174939 * A321315 A203225 A308386

Adjacent sequences:  A320797 A320798 A320799 * A320801 A320802 A320803

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Nov 02 2018

STATUS

approved

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Last modified July 9 22:46 EDT 2020. Contains 335570 sequences. (Running on oeis4.)