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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
1, 1, 2, 6, 18, 70, 300, 1435, 7910, 47376, 316008, 2314158, 18331236, 158024724, 1462752720, 14497475850, 153488070450 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
S. Kitaev, Introduction to partially ordered patterns, Discrete Applied Mathematics 155 (2007), 929-944.
Rémy Sigrist, C program
PROG
(C) See Links section.
CROSSREFS
Sequence in context: A006389 A030269 A150082 * A060181 A131281 A264036
KEYWORD
nonn,more
AUTHOR
Signy Olafsdottir (signy06(AT)ru.is), May 09 2010
EXTENSIONS
a(0) = 1 and a(10)-a(16) from Rémy Sigrist, Mar 13 2023
STATUS
approved

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Last modified April 23 12:27 EDT 2024. Contains 371912 sequences. (Running on oeis4.)