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Search: id:A104001
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| A104001 |
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Triangle T(n,k) read by rows: number of permutations in S_n avoiding all k-length patterns starting with fixed m, 2<k<=n, 1<=m<=k. |
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+0
1
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| 2, 4, 6, 8, 18, 24, 16, 54, 96, 120, 32, 162, 384, 600, 720, 64, 486, 1536, 3000, 4320, 5040, 128, 1458, 6144, 15000, 25920, 35280, 40320, 256, 4374, 24576, 75000, 155520, 246960, 322560, 362880, 512, 13122, 98304, 375000, 933120, 1728720
(list; table; graph; listen)
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OFFSET
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3,1
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LINKS
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T. Mansour, Permutations containing and avoiding certain patterns
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FORMULA
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T(n, k) = (k-2)! * (k-1)^(n+1-k).
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EXAMPLE
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2
4,6
8,18,24
16,54,96,120
32,162,384,600,720
64,486,1536,3000,4320,5040
128,1458,6144,15000,25920,35280,40320
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CROSSREFS
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Adjacent sequences: A103998 A103999 A104000 this_sequence A104002 A104003 A104004
Sequence in context: A100778 A122408 A100055 this_sequence A048784 A133296 A076402
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KEYWORD
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nonn,tabl
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AUTHOR
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Ralf Stephan, Feb 26 2005
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