The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A165542 Number of permutations of length n which avoid the patterns 4231 and 4123. 4
 1, 1, 2, 6, 22, 89, 380, 1677, 7566, 34676, 160808, 752608, 3548325, 16830544, 80234659, 384132724, 1845829988, 8897740300, 43010084460, 208409687323, 1012046126532, 4923952560917, 23997719075657, 117136530812812, 572552052378494, 2802078324448067 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS G.f. conjectured to be non-D-finite (see Albert et al link). - Jay Pantone, Oct 01 2015 LINKS David Bevan, Jay Pantone, and Nathaniel Shar, Table of n, a(n) for n = 0..1000 (terms 1 through 40 by David Bevan, terms 41 through 70 by Nathaniel Shar) Michael H. Albert, Cheyne Homberger, Jay Pantone, Nathaniel Shar, Vincent Vatter, Generating Permutations with Restricted Containers, arXiv:1510.00269 [math.CO], 2015. C. Bean, M. Tannock and H. Ulfarsson, Pattern avoiding permutations and independent sets in graphs, arXiv:1512.08155 [math.CO], 2015. Darla Kremer and Wai Chee Shiu, Finite transition matrices for permutations avoiding pairs of length four patterns, Discrete Math. 268 (2003), 171-183. MR1983276 (2004b:05006). See Table 1. Wikipedia, Permutation classes avoiding two patterns of length 4. EXAMPLE There are 22 permutations of length 4 which avoid these two patterns, so a(4)=22. CROSSREFS Cf. A053614, A106228, A165542, A165545, A257561, A257562. Sequence in context: A363809 A111053 A165541 * A165543 A049123 A200753 Adjacent sequences: A165539 A165540 A165541 * A165543 A165544 A165545 KEYWORD nonn AUTHOR Vincent Vatter, Sep 21 2009 EXTENSIONS More terms from David Bevan, Feb 04 2014 a(0)=1 prepended by Jay Pantone, Oct 01 2015 STATUS approved

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

Last modified September 9 14:53 EDT 2024. Contains 375764 sequences. (Running on oeis4.)