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A356697
Number of Catalan words of length n avoiding the pattern 0000.
3
1, 1, 2, 5, 13, 36, 101, 280, 788, 2212, 6186, 17384, 48755, 136649, 383584, 1075734, 3016924, 8464693, 23740844, 66592246, 186807727, 523973400, 1469769653, 4122833303, 11564436141, 32438795011, 90992182917, 255234015580, 715941436278, 2008237780651
OFFSET
0,3
LINKS
Jean-Luc Baril, Sergey Kirgizov and Vincent Vajnovszki, Descent distribution on Catalan words avoiding a pattern of length at most three, arXiv:1803.06706 [math.CO], 2018.
FORMULA
G.f.: -(3*x^5-9*x^3-2*x^2+1)/((x-1)*(x^5-5*x^4-12*x^3-3*x^2+1)).
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Aug 23 2022
STATUS
approved