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A104001 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. 1
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; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Table of n, a(n) for n=3..44.

T. Mansour, Permutations containing and avoiding certain patterns

FORMULA

T(n, k) = (k-2)! * (k-1)^(n+1-k).

EXAMPLE

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

CROSSREFS

Sequence in context: A122408 A100055 A304660 * A048784 A152491 A133296

Adjacent sequences:  A103998 A103999 A104000 * A104002 A104003 A104004

KEYWORD

nonn,tabl

AUTHOR

Ralf Stephan, Feb 26 2005

STATUS

approved

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Last modified February 22 23:03 EST 2019. Contains 320411 sequences. (Running on oeis4.)