OFFSET
0,4
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
J.-L. Baril, J.-M. Pallo, Motzkin subposet and Motzkin geodesics in Tamari lattices, 2013.
FORMULA
a(n) ~ 3^(n+3/2) / (2*sqrt(Pi)*n^(3/2)). - Vaclav Kotesovec, Apr 28 2014
D-finite with recurrence: (n-3)*(n+1)*a(n) = n*(4*n-11)*a(n-1) - 3*(n-1)*a(n-2) - (n-2)*(8*n-21)*a(n-3) - 3*(n-3)*(n-2)*a(n-4). - Vaclav Kotesovec, Apr 28 2014
MATHEMATICA
CoefficientList[Series[(1 - x) (1 - x-2 x^2 - Sqrt[1 - 2 x - 3 x^2])/(2 x (1 - 2 x - x^2)), {x, 0, 40}], x] (* Vincenzo Librandi, Apr 28 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 24 2013
EXTENSIONS
Offset changed (from 1 to 0) and more terms added by Vincenzo Librandi, Apr 28 2014
STATUS
approved