1,3
Table of n, a(n) for n=1..6.
a(3) = binomial(3*2,2*1-1) = binomial(6,1) = 6.
Cf. A001906, A090162.
Sequence in context: A001326 A089501 A187083 * A093884 A079183 A030245
Adjacent sequences: A114181 A114182 A114183 * A114185 A114186 A114187
nonn
Greg Huber (huber(AT)alum.mit.edu), Feb 04 2006
approved