1,3

By 'binary tree' we mean a rooted, ordered tree in which each vertex has either 0 or 2 children.

Eric S. Rowland, Pattern avoidance in binary trees.

Generating function f(x) satisfies -x f(x)^3 + (x-1) x f(x)^2 + (x-1)^2 f(x) + (x-1) x = 0

Sequence in context: A159773 A159769 A159771 this_sequence A128739 A036766 A148322

Adjacent sequences: A159765 A159766 A159767 this_sequence A159769 A159770 A159771

nonn

Eric S Rowland (erowland(AT)math.rutgers.edu), Apr 23 2009