A080299 A014486-encoding of plane binary trees (Stanley's d) whose interior zigzag-tree (Stanley's c, i.e., tree obtained by discarding the outermost edges of the binary tree) is isomorphic to a valid plane binary tree (Stanley's d).

2, 50, 818, 914, 13106, 13202, 14642, 14738, 15506, 209714, 209810, 211250, 211346, 212114, 234290, 234386, 235826, 235922, 236690, 248114, 248210, 248978, 255122, 3355442, 3355538, 3356978, 3357074, 3357842, 3380018, 3380114, 3381554

Offset

0,1

Comments

These trees are obtained by replacing each non-root terminal node (a leaf) of the binary tree with a branch of two leaves, i.e., "." -> "\/".

Links

Table of n, a(n) for n=0..30.

A. Karttunen, Nine initial trees can be found here (The trees with the ordinal numbers 1., 6., 39., 53., 345., 359., 477., 491. and 567.)

R. P. Stanley, Exercises on Catalan and Related Numbers

Formula

a(n) = A080310(A014486(n)).

Crossrefs

a(n) = A014486(A080298(n)). Breadth-first-wise encoding: A080313.

Sequence in context: A048610 A007511 A016032 * A083939 A083941 A080263

Adjacent sequences: A080296 A080297 A080298 * A080300 A080301 A080302

Keyword

nonn

Author

Antti Karttunen, Mar 02 2003

Status

approved