OFFSET
1,3
COMMENTS
By 'binary tree' we mean a rooted, ordered tree in which each vertex has either 0 or 2 children.
LINKS
CombOS - Combinatorial Object Server, Generate binary trees
Petr Gregor, Torsten Mütze, and Namrata, Combinatorial generation via permutation languages. VI. Binary trees, arXiv:2306.08420 [cs.DM], 2023.
Eric S. Rowland, Pattern avoidance in binary trees, arXiv:0809.0488 [math.CO], 2008-2010.
FORMULA
G.f. f(x) satisfies -x f(x)^3 + (x-1) x f(x)^2 + (x-1)^2 f(x) + (x-1) x = 0.
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric Rowland, Apr 23 2009
STATUS
approved