

A193285


Number of forbidden patterns of length n of the map f(x) = 4x(1x) on the unit interval. A permutation pi is a forbidden pattern if there is no x in [0,1] such that the values x,f(x),f(f(x)),...,f^{n1}(x) are in the same relative order as pi_1,pi_2,...,pi_n.


3



0, 0, 0, 1, 12, 89, 645, 4862, 39906, 361931, 3626663, 39912033
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OFFSET

0,5


COMMENTS

a(n) is also the number of forbidden patterns of length n of the tent map x > 112x in [0,1].


LINKS

Table of n, a(n) for n=0..11.
S. Elizalde and Y. Liu, On basic forbidden patterns of functions, Discrete Appl. Math. 159 (2011), 12071216.


FORMULA

a(n) = n!  A193284(n).


EXAMPLE

a(3) = 1 because the only forbidden pattern of length 3 is 321.


CROSSREFS

Cf. A000142, A193284 (allowed patterns).
Sequence in context: A012088 A083825 A181944 * A199558 A034197 A217089
Adjacent sequences: A193282 A193283 A193284 * A193286 A193287 A193288


KEYWORD

nonn,more


AUTHOR

Sergi Elizalde, Jul 20 2011


EXTENSIONS

a(0)=0 prepended by Alois P. Heinz, Mar 02 2020


STATUS

approved



