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A306319 Number of length-rectangular twice-partitions of n. 8
1, 1, 3, 5, 10, 14, 26, 35, 60, 82, 131, 177, 286, 376, 582, 793, 1202, 1610, 2450, 3274, 4906, 6665, 9770, 13274, 19690, 26506, 38596, 53006, 76432, 104189, 150844, 205282, 294304, 404146, 573140, 786169, 1119457, 1527554, 2155953, 2965567, 4163955, 5701816 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

A twice partition of n is a sequence of integer partitions, one of each part in an integer partition of n. It is length-rectangular if all parts have the same number of parts.

LINKS

Table of n, a(n) for n=0..41.

EXAMPLE

The a(5) = 14 length-rectangular twice-partitions:

[5] [4 1] [3 2] [3 1 1] [2 2 1] [2 1 1 1] [1 1 1 1 1]

.

[4] [3] [2 1]

[1] [2] [1 1]

.

[3] [2]

[1] [2]

[1] [1]

.

[2]

[1]

[1]

[1]

.

[1]

[1]

[1]

[1]

[1]

MATHEMATICA

Table[Length[Join@@Table[Select[Tuples[IntegerPartitions/@ptn], SameQ@@Length/@#&], {ptn, IntegerPartitions[n]}]], {n, 20}]

CROSSREFS

Dominates A319066 (rectangular partitions of partitions), which dominates A323429 (rectangular plane partitions).

Cf. A000219, A001970, A063834 (twice-partitions), A089299, A271619, A279787 (sum-rectangular twice-partitions), A305551, A306017, A306318 (square case), A323531.

Sequence in context: A092269 A323429 A319066 * A182722 A089483 A323858

Adjacent sequences: A306316 A306317 A306318 * A306320 A306321 A306322

KEYWORD

nonn

AUTHOR

Gus Wiseman, Feb 07 2019

STATUS

approved

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Last modified March 30 14:20 EDT 2023. Contains 361622 sequences. (Running on oeis4.)