A319560 - OEIS

A319560

Number of non-isomorphic strict T_0 multiset partitions of weight n.

1, 1, 2, 6, 15, 40, 121, 353, 1107, 3550, 11818

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OFFSET

0,3

COMMENTS

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.

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) = 15 multiset partitions:

1: {{1}}

2: {{1,1}}

{1},{2}}

3: {{1,1,1}}

{{1},{1,1}}

{{1},{2,2}}

{{2},{1,2}}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A007716, A007718, A049311, A053419, A056156, A059201, A283877, A316980.

Cf. A319557, A319558, A319559, A319564, A319565, A319566, A319567.

Sequence in context: A062106 A206000 A316981 * A061322 A004664 A074446

Adjacent sequences: A319557 A319558 A319559 * A319561 A319562 A319563

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Sep 23 2018

STATUS

approved