The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A193285 Number of forbidden patterns of length n of the map f(x) = 4x(1-x) 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^{n-1}(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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS a(n) is also the number of forbidden patterns of length n of the tent map x -> 1-|1-2x| in [0,1]. LINKS S. Elizalde and Y. Liu, On basic forbidden patterns of functions, Discrete Appl. Math. 159 (2011), 1207-1216. 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 13 02:47 EDT 2021. Contains 342934 sequences. (Running on oeis4.)