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A141254 Number of permutations that lie in the cyclic closure of Av(123) - i.e., at least one cyclic rotation of the permutation avoids the pattern 123. 1
1, 1, 2, 6, 24, 110, 510, 2268, 9632, 39492, 158190, 624745, 2447808, 9552244, 37214086, 144932760, 564676096, 2201735552, 8592780798, 33568042425, 131261440720, 513747571680, 2012524130518, 7890178181831, 30957296889264 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..24.

M. D. Atkinson, M. H. Albert, R. E. L. Aldred, H. P. van Ditmarsch, C. C. Handley, D. A. Holton, D. J. McCaughan, C. Monteith, Cyclically closed pattern classes of permutations, Australasian J. Combinatorics 38 (2007), 87-100.

FORMULA

a(n) = n * (C(n) - 2^n + binomial(n,2) + 2) for n >= 4.

EXAMPLE

a(5)=110 because 110 permutations of length 5 have at least one cyclic rotation which avoids 123.

CROSSREFS

Cf. A141253.

Sequence in context: A230695 A177519 A214762 * A216879 A138020 A046646

Adjacent sequences:  A141251 A141252 A141253 * A141255 A141256 A141257

KEYWORD

nonn

AUTHOR

Vincent Vatter, Jun 17 2008

STATUS

approved

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Last modified June 24 17:51 EDT 2021. Contains 345419 sequences. (Running on oeis4.)