The Riordan group is a group of infinite lower triangular matrices that are defined by two generating functions, g and f. The kth column of the matrix has the generating function gf k. In the Double Riordan group there are two generating function f 1 and f 2 such that the columns, starting at the left, have generating functions using f 1 and f 2… (More)
Most of people knows the following problem, What is the next term ? What expression would give us the general term ? It would be nice to have a formula to generate all the terms in the sequence. how do we find the formula? here is the way to become a 'genius' at MENSA tests.
In this paper we compute the distribution of several statistics on the set of rooted ordered trees. In particular, we determine the number of boundary edges, the number of singleton boundary edges, and the analogous values when edges may take on one of k colors.