A193935 4-nonnesting permutations.

1, 2, 6, 24, 120, 720, 5034, 40087, 356942, 3500551, 37343168, 428886219, 5257753614, 68306562647, 934747457369, 13404687958473, 200554264435218, 3118638648191005, 50236367074036768, 835860362285064716

Offset

1,2

Comments

Also the number of 4-noncrossing permutations.

Links

Table of n, a(n) for n=1..20.

Sophie Burrill, Sergi Elizalde, Marni Mishna and Lily Yen, A generating tree approach to k-nonnesting partitions and permutations, arXiv preprint arXiv:1108.5615 [math.CO], 2011-2014.

S. Corteel, Crossings and alignments of permutations, Adv. Appl. Math 38 (2007) 149-163.

Crossrefs

Cf. A193938, A193936, A193937.

Sequence in context: A177547 A324136 A177548 * A177534 A164873 A226438

Adjacent sequences: A193932 A193933 A193934 * A193936 A193937 A193938

Keyword

nonn,more

Author

Lily Yen, Aug 09 2011

Status

approved