

A321484


Number of nonisomorphic selfdual connected multiset partitions of weight n.


0



1, 1, 1, 2, 3, 6, 9, 20, 35, 78, 141
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OFFSET

0,4


COMMENTS

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

Nonisomorphic representatives of the a(1) = 1 through a(6) = 9 multiset partitions:
{{1}} {{11}} {{111}} {{1111}} {{11111}} {{111111}}
{{2}{12}} {{12}{12}} {{11}{122}} {{112}{122}}
{{2}{122}} {{12}{122}} {{12}{1222}}
{{2}{1222}} {{2}{12222}}
{{2}{13}{23}} {{22}{1122}}
{{3}{3}{123}} {{12}{13}{23}}
{{2}{13}{233}}
{{3}{23}{123}}
{{3}{3}{1233}}


CROSSREFS

Cf. A007718, A056156, A138178, A316983, A319565, A319616, A319647, A319719, A321194, A321585, A321680, A321681.
Sequence in context: A320169 A293606 A185376 * A191469 A091053 A095064
Adjacent sequences: A321481 A321482 A321483 * A321485 A321486 A321487


KEYWORD

nonn,more


AUTHOR

Gus Wiseman, Nov 16 2018


STATUS

approved



