The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A177470 Avoiding the pattern 11'22'. To avoid 11'22' means not to have four consecutive letters such that the first letter is less than the third one and the second letter is less than the fourth one. 4

%I #10 Mar 13 2023 17:48:22

%S 1,1,2,6,18,70,300,1435,7910,47376,316008,2314158,18331236,158024724,

%T 1462752720,14497475850,153488070450

%N Avoiding the pattern 11'22'. To avoid 11'22' means not to have four consecutive letters such that the first letter is less than the third one and the second letter is less than the fourth one.

%H S. Kitaev, <a href="https://doi.org/10.1016/j.dam.2006.09.011">Introduction to partially ordered patterns</a>, Discrete Applied Mathematics 155 (2007), 929-944.

%H Rémy Sigrist, <a href="/A177470/a177470.txt">C program</a>

%o (C) See Links section.

%Y Cf. A177471-A177476.

%K nonn,more

%O 1,3

%A Signy Olafsdottir (signy06(AT)ru.is), May 09 2010

%E a(0) = 1 and a(10)-a(16) from _Rémy Sigrist_, Mar 13 2023

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 21 22:16 EDT 2024. Contains 372741 sequences. (Running on oeis4.)