We consider plane rooted trees on n+1 vertices without branching points on odd levels. The number of such trees in equal to the Motzkin number M n . We give a bijective proof of this statement.
Motzkin Numbers
β Scribed by M. Aigner
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 178 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0195-6698
No coin nor oath required. For personal study only.
β¦ Synopsis
In this paper Motzkin numbers M n (which are related to Catalan numbers) are studied. The (known) connection to Tchebychev polynomials is discussed with applications to the Hankel matrices of Motzkin numbers. It is shown that the sequence M n is logarithmically concave with lim M n+1 /M n = 3. Finally, two ballot-number type sequences for M n are derived, with an application to directed animals.
π SIMILAR VOLUMES
We use combinatorial methods to evaluate Hankel determinants for the sequence of sums of consecutive t-Motzkin numbers. More specifically, we consider the following determinant: where t is a real number and m t k is the total weight of all paths from (0, 0) to (k, 0) that stay above the x-axis and
We prove various congruences for Catalan and Motzkin numbers as well as related sequences. The common thread is that all these sequences can be expressed in terms of binomial coefficients. Our techniques are combinatorial and algebraic: group actions, induction, and Lucas' congruence for binomial co