A319557 - OEIS

A319557

Number of non-isomorphic strict connected multiset partitions of weight n.

1, 1, 2, 5, 12, 30, 91, 256, 823, 2656, 9103, 31876, 116113, 432824, 1659692, 6508521, 26112327, 106927561, 446654187, 1900858001, 8236367607, 36306790636, 162724173883, 741105774720, 3428164417401, 16099059101049, 76722208278328, 370903316203353, 1818316254655097

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OFFSET

0,3

COMMENTS

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

Also the number of non-isomorphic connected T_0 multiset partitions of weight n. In a multiset partition, two vertices are equivalent if in every block the multiplicity of the first is equal to the multiplicity of the second. The T_0 condition means that there are no equivalent vertices.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..50

FORMULA

Inverse Euler transform of A316980.

EXAMPLE

Non-isomorphic representatives of the a(4) = 12 strict connected multiset partitions:

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

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

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

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

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

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

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

Non-isomorphic representatives of the a(4) = 12 connected T_0 multiset partitions:

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A007716, A007718, A049311, A056156, A283877, A316980.

Cf. A319558, A319559, A319560, A319564, A319565, A319566, A319567.

Sequence in context: A261788 A112412 A309506 * A261937 A305311 A291239

Adjacent sequences: A319554 A319555 A319556 * A319558 A319559 A319560

KEYWORD

nonn

AUTHOR

Gus Wiseman, Sep 23 2018

EXTENSIONS

Terms a(11) and beyond from Andrew Howroyd, Jan 19 2023

STATUS

approved