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

Author

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

Keywords

• nonn

Links

• 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).