686119227300
domain: N
Appears in sequences
- a(n) = (1/(4n-1))*C(4n,2n).at n=12A024491
- Dirichlet convolution of Catalan numbers (1,2,5,14...) with themselves.at n=22A034717
- Expansion of (1 + x*C)*C, where C = (1 - (1 - 4*x)^(1/2))/(2*x) is the g.f. for Catalan numbers, A000108.at n=23A068875
- The number of boundary twigs for complete binary twigs. A twig is a vertex with one edge on the boundary and only one other descendant.at n=22A228403
- Number of rooted asymmetrical polyenoids of type U_n* having n edges.at n=23A262543
- a(-1)=-1; a(n) = 2*A000108(n) for n >= 0.at n=24A284016