

A289451


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


0



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

1,4


LINKS



FORMULA

a(n) = binomial(2*n,n)/(n+1)  (n1)*n/2.
G.f.: (1sqrt(14*x))/(2*x)  x^2/((1x))^3. (End)


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



