%N a(n) is the number of unimodular triangulations of [0,2]x[0,n].
%C As stated by Kaibel and Ziegler, the number of unimodular triangulations of [0,1]x[0,n] is (2n)!/(n!*n!). This gives a(1)=6.
%C No formula for a(n) is known. Aichholzer computed a(n) for n<=15.
%C Kaibel and Ziegler computed a(n) for n<=375. Aichholzer also computed the number of unimodular triangulations of [0,m]x[0,n] for m=3,4,5 and various n, and Kaibel-Ziegler extended these calculations to m=6.
%D V. Kaibel and G. Ziegler, "Counting lattice triangulations," London Math. Soc. Lecture Notes Series, Vol. 307, pp. 277-307, 2003.
%H O. Aichholzer, <a href="http://www.ist.tugraz.at/aichholzer/research/rp/triangulations/counting/">Counting Triangulations - Olympics</a>, 2006.
%H V. Kaibel and G. M. Ziegler, <a href="http://arXiv.org/abs/math.CO/0211268">Counting Lattice Triangulations</a>, arXiv:math/0211268 [math.CO], 2002.
%Y Second column of array A082640.
%A _John Kieffer_, Dec 06 2017