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A127119 Triangle read by rows: T(n,k) = number of endofunctions on a set with n elements, where the maximum indegree is k. 1
1, 2, 1, 3, 3, 1, 5, 10, 3, 1, 7, 24, 12, 3, 1, 11, 64, 39, 12, 3, 1, 15, 149, 122, 41, 12, 3, 1, 22, 366, 368, 138, 41, 12, 3, 1, 30, 857, 1092, 439, 140, 41, 12, 3, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..45.

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 have node 1 with indegree 2 and the final 3 are permutations, each node having indegree 1. So row 3 of the triangle is 3,3,1.

The triangle starts:

1

2 1

3 3 1

5 10 3 1

7 24 12 3 1

CROSSREFS

Sequence in context: A122075 A185675 A153341 * A322265 A066704 A262917

Adjacent sequences:  A127116 A127117 A127118 * A127120 A127121 A127122

KEYWORD

more,nonn,tabl

AUTHOR

Franklin T. Adams-Watters, Jan 05 2007

STATUS

approved

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Last modified November 21 04:47 EST 2019. Contains 329350 sequences. (Running on oeis4.)