A153246 Number of fleeing trees computed for Catalan bijection A057164.

0, 0, 0, 1, 0, 1, 1, 1, 2, 0, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 3, 0, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 0, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3

Offset: 0

Author

Antti Karttunen, Dec 22 2008

Keywords

• nonn

Comments

A "fleeing tree" sequence computed for Catalan bijection CatBij gives for each binary tree A014486(n) the number of cases where, when a new V-node (a bud) is inserted into one of the A072643(n)+1 possible leaves of that tree, it follows that (CatBij tree) is not a subtree of (CatBij tree-with-bud-inserted). I.e., for each tree A014486(n), we compute Sum_{i=0}^A072643(n) (1 if catbij(n) is a subtree of catbij(A153250bi(n,i)), 0 otherwise). Here A153250 gives the bud-inserting operation. Note that for any Catalan Bijection, which is an image of "psi" isomorphism (see A153141) from the Automorphism Group of infinite binary trees, the result will be A000004, the zero-sequence. To satisfy that condition, CatBij should at least satisfy A127302(CatBij(n)) = A127302(n) for all n (clearly A057164 does not satisfy that, so we got nonzero terms here). However, that is just a necessary but not a sufficient condition. For example, A123493 & A123494 satisfy it, but they still produce nonzero sequences: A153247, A153248.

Crossrefs

Cf. A082858, A153250, A153247, A153248.