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A335793 Number of hare pop-stack sortable Cayley permutations. 0
1, 1, 3, 11, 41, 151, 553, 2023, 7401 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also, the set of Cayley permutations avoiding 231, 312, and 2121.

LINKS

Table of n, a(n) for n=0..8.

Giulio Cerbai, Sorting Cayley permutations with pattern-avoiding machines, arXiv:2003.02536 [math.CO], 2020. See p. 16.

FORMULA

Conjectures from Colin Barker, Jun 24 2020: (Start)

G.f.: (1 - 4*x + 4*x^2 - 2*x^3) / (1 - 5*x + 6*x^2 - 4*x^3).

a(n) = 5*a(n-1) - 6*a(n-2) + 4*a(n-3) for n>3.

(End)

CROSSREFS

Cf. A000670, A226316.

Sequence in context: A086972 A218348 A320827 * A077831 A032952 A001835

Adjacent sequences:  A335790 A335791 A335792 * A335794 A335795 A335796

KEYWORD

nonn,more

AUTHOR

Michael De Vlieger, Jun 23 2020

EXTENSIONS

a(7)-a(8) from Giulio Cerbai via Michael De Vlieger, Jun 24 2020

STATUS

approved

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Last modified April 21 15:26 EDT 2021. Contains 343154 sequences. (Running on oeis4.)