A177472 Number of permutations of order n avoiding the consecutive pattern 11'2'2.

1, 1, 2, 6, 18, 71, 322, 1665, 9789, 64327, 468914, 3748920, 32699022, 308710917, 3138821688, 34186918427, 397173376849, 4902547569617, 64073734206528, 883940288032392, 12836250526983672, 195724485831901029, 3126468139092090818, 52211816154041174670, 909843384081141844312

Offset: 0

Author

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

Keywords

• nonn

Comments

To avoid 11'2'2 means not to have four consecutive letters such that the first letter is less than the last one, and the second letter is less than the third one.

Links

• S. Kitaev, Introduction to partially ordered patterns, Discrete Applied Mathematics 155 (2007), 929-944.

Crossrefs

Cf. A117156, A177470, A177471, A177473, A177475, A177476, A177477, A177478, A177479, A177480, A177481, A177482, A177483, A177484, A376694.

Extensions

Edited and terms a(0), a(10)-a(24) added by Max Alekseyev, Oct 02 2024