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A309506
Number of cyclic permutations of length n avoiding the pattern 231 (equivalently, 312).
3
1, 1, 1, 2, 5, 12, 30, 86, 253, 748, 2274, 7152
OFFSET
1,4
LINKS
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
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