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A316981 Number of non-isomorphic strict multiset partitions of weight n with no equivalent vertices. 5
1, 1, 2, 6, 15, 40, 121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also the number of nonnegative integer n X n matrices with sum of elements equal to n, under row and column permutations, with no equal rows and no equal columns.

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.

LINKS

Table of n, a(n) for n=0..6.

EXAMPLE

Non-isomorphic representatives of the a(3) = 6 strict multiset partitions with no equivalent vertices (first column) and their duals (second column):

      (111) <-> (111)

      (122) <-> (1)(11)

    (1)(11) <-> (122)

    (1)(22) <-> (1)(22)

    (2)(12) <-> (2)(12)

  (1)(2)(3) <-> (1)(2)(3)

CROSSREFS

Cf. A000009, A001055, A007716, A007717, A020555, A045778.

Cf. A316974, A316978, A316979, A316980, A316983.

Sequence in context: A001654 A062106 A206000 * A319560 A061322 A004664

Adjacent sequences:  A316978 A316979 A316980 * A316982 A316983 A316984

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Jul 18 2018

STATUS

approved

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Last modified July 15 04:34 EDT 2020. Contains 335763 sequences. (Running on oeis4.)