A309506 Number of cyclic permutations of length n avoiding the pattern 231 (equivalently, 312).

1, 1, 1, 2, 5, 12, 30, 86, 253, 748, 2274, 7152

Offset

1,4

Links

Table of n, a(n) for n=1..12.

Miklos Bona, Michael Cory, Cyclic Permutations Avoiding Pairs of Patterns of Length Three, arXiv:1805.05196 [math.CO], 2018.

Example

For n=4, there are two such permutations, 4123 and 4312.

Crossrefs

Cf. A309504, A309505, A309508.

Sequence in context: A363912 A261788 A112412 * A319557 A261937 A305311

Adjacent sequences: A309503 A309504 A309505 * A309507 A309508 A309509

Keyword

nonn,more

Author

Miklos Bona, Aug 05 2019

Extensions

a(1)=1 (confirmed by author) inserted by Alexander Burstein, Jul 20 2020

Status

approved