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Search: id:A135021
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| A135021 |
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Triangle read by rows: T(n,r) = number of maximum r-uniform acyclic hypergraphs of order n and size n-r+1. |
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1
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| 1, 1, 1, 1, 3, 1, 1, 16, 6, 1, 1, 125, 70, 10, 1, 1, 1296, 1215, 200, 15, 1, 1, 16807, 27951, 5915, 455, 21, 1, 1, 262144, 799708, 229376, 20230, 896, 28, 1, 1, 4782969, 27337500, 10946964, 1166886, 55566, 1596, 36, 1, 1, 100000000, 1086190605, 618435840, 82031250, 4429152, 131250, 2640, 45, 1, 1, 2357947691, 49162945645, 40283203125, 6768679170, 426666702, 13763442, 277530, 4125, 55, 1
(list; table; graph; listen)
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OFFSET
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1,5
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LINKS
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Wang, Jian-fang and Li, Hai-zhu, Enumeration of Maximum Acyclic Hypergraphs, Acta Mathematicae Applicatae Sinica,English Series, 2002 vol.18 number 2, page 215.
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FORMULA
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T(n,r)=C(n,r-1)(n(r-1)-r^2+2r)^(n-r-1)
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MAPLE
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seq(seq(binomial(n, r-1)*(n*(r-1)-r^2+2*r)^(n-r-1), r=1..n), n=1..11);
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CROSSREFS
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Adjacent sequences: A135018 A135019 A135020 this_sequence A135022 A135023 A135024
Sequence in context: A144270 A110112 A060325 this_sequence A087987 A121412 A016561
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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John Nnamdi (john_info_2008(AT)bbvczx.com), Feb 10 2008
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