OFFSET
0,1
LINKS
Lars Blomberg, Table of n, a(n) for n = 0..99
Andrei Asinowski, Christian Krattenthaler, Toufik Mansour, Counting triangulations of some classes of subdivided convex polygons, arXiv:1604.02870 [math.CO], 2016.
FORMULA
From Asinowski and Krattenthaler equation 2.7: a(n) = tr(4,n+1). - Lars Blomberg, Mar 04 2017
MATHEMATICA
F[n_] := F[n] = Expand[F[n - 2] t + F[n - 1]]; F[1] = 1; F[0] = 1;
cee = Function[{n}, Total@MapIndexed[(#1 CatalanNumber[4 n - #2[[1]] - 1] (-1)^(#2[[1]] + 1)) &, CoefficientList[F[n]^4, t]]];
Table[cee[n], {n, 20}] (* Adam P. Goucher, Nov 23 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 03 2017
EXTENSIONS
More terms from Lars Blomberg, Mar 04 2017
STATUS
approved