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A127121 Number of endofunctions on a set, where the multiset of indegrees forms the n-th partition in Mathematica order (ignoring 0's). 1
1, 1, 1, 2, 1, 3, 3, 1, 3, 3, 7, 5, 1, 3, 4, 8, 10, 14, 7, 1, 3, 4, 8, 3, 19, 17, 6, 32, 26, 11, 1, 3, 4, 8, 4, 19, 18, 11, 14, 63, 34, 29, 75, 45, 15, 1, 3, 4, 8, 4, 19, 18, 3, 20, 14, 64, 37, 14, 39, 85, 168, 62, 15, 109, 167, 75, 22, 1, 3, 4, 8, 4, 19, 18, 4, 20, 14, 64, 38, 11, 26, 71 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Can be regarded as a triangle with one row for each size of partition.

LINKS

Table of n, a(n) for n=0..81.

EXAMPLE

For n = 3, the 7 endofunctions are (1,2,3) -> (1,1,1), (1,1,2), (1,2,1), (2,1,1), (1,2,3), (1,3,2) and (2,3,1). In the first, node 1 has indegree 3, the next 3 node 1 has indegree 2 and node 2 has indegree 1 (forming partition [2,1]) and the final 3 are permutations, each node having indegree 1. The partitions of 3 in Mathematica order are [3], [2,1], [1^3], so row 3 of the triangle is 1,3,3.

The triangle starts:

1

1

1 2

1 3 3

1 3 3 7 5

1 3 4 8 10 14 7

CROSSREFS

Sequence in context: A162910 A098975 A309213 * A238703 A185908 A234951

Adjacent sequences:  A127118 A127119 A127120 * A127122 A127123 A127124

KEYWORD

nonn,tabf

AUTHOR

Franklin T. Adams-Watters, Jan 05 2007

STATUS

approved

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Last modified October 14 18:28 EDT 2019. Contains 328022 sequences. (Running on oeis4.)