A289451 Related to number of mesh patterns of length 2 that avoid the pattern 231.

1, 1, 1, 2, 8, 32, 117, 408, 1402, 4826, 16751

Offset

1,4

Links

Table of n, a(n) for n=1..11.

Murray Tannock, Equivalence classes of mesh patterns with a dominating pattern, MSc Thesis, Reykjavik Univ., May 2016. See Appendix B1.

Formula

Conjectures from Vladimir Kruchinin, Jan 06 2022: (Start)

a(n) = binomial(2*n,n)/(n+1) - (n-1)*n/2.

G.f.: (1-sqrt(1-4*x))/(2*x) - x^2/((1-x))^3. (End)

Crossrefs

Sequence in context: A067897 A145682 A363109 * A230509 A099752 A230393

Adjacent sequences: A289448 A289449 A289450 * A289452 A289453 A289454

Keyword

nonn,more

Author

N. J. A. Sloane, Jul 08 2017

Status

approved