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Search: id:A127119
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| A127119 |
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Triangle read by rows: T(n,k) = number of endofunctions on a set with n elements, where the maximum indegree is k. |
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2
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| 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; listen)
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OFFSET
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1,2
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EXAMPLE
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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
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CROSSREFS
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Adjacent sequences: A127116 A127117 A127118 this_sequence A127120 A127121 A127122
Sequence in context: A100578 A061315 A122075 this_sequence A066704 A127123 A103525
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KEYWORD
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more,nonn,tabl
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AUTHOR
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Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Jan 05 2007
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