\begin{abstract} For the analysis of an algorithm to generate binary trees \cite{XiTaUs97}, the behaviour of a certain sequence of numbers is essential. In the original paper, it was expressed by a recursion. Here, we show how to solve this (and similar) recursions, both, explicitly and asymptotically. Some additional information about useful mathematical software is also provided. \end{abstract}
helmut@gauss.cam.wits.ac.za,