A011272 Hybrid binary rooted trees with n nodes whose root is labeled by "a".

0, 1, 3, 13, 64, 339, 1885, 10851, 64109, 386510, 2368354, 14706331, 92337618, 585239903, 3739309053, 24059542845, 155756019048, 1013801283133, 6630587014935, 43553555324502

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Nancy S. S. Gu, Nelson Y. Li, and Toufik Mansour, 2-Binary trees: bijections and related issues, Discr. Math., 308 (2008), 1209-1221.

J. M. Pallo, On the listing and random generation of hybrid binary trees, International Journal of Computer Mathematics, 50 (1994) 135-145.

Index entries for sequences related to rooted trees

Formula

a(n) = A007863(n) - A011270(n).

Crossrefs

Sequence in context: A349304 A372507 A283667 * A367062 A366026 A200719

Adjacent sequences: A011269 A011270 A011271 * A011273 A011274 A011275

Keyword

nonn

Author

Jean Pallo (pallo(AT)u-bourgogne.fr)

Status

approved