A321681 - OEIS

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A321681

Number of non-isomorphic weight-n connected strict antichains of multisets with multiset density -1.

1, 1, 2, 3, 7, 13, 35, 77, 205, 517, 1399

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OFFSET

0,3

COMMENTS

The multiset density of a multiset partition is the sum of the numbers of distinct vertices in each part minus the number of parts minus the number of 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(5) = 13 trees:

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

{{1,3},{2,3}} {{1,2,3,4,5}}

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

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

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

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

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

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

CROSSREFS

Cf. A006126, A007718, A056156, A096827, A285572, A293993, A293994, A305052, A319557, A319565, A319719, A319721, A321585, A321680.

Sequence in context: A280765 A056953 A371867 * A045611 A006840 A123408

Adjacent sequences: A321678 A321679 A321680 * A321682 A321683 A321684

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Nov 16 2018

STATUS

approved