A Coin-Tossing Problem and Some Related Combinatorics
Roger H. Moritz, Robert C. Williams · Mathematics Magazine · 1988
We first establish our notation. We set p = P(head) and q = 1 p = P(tail). When referring to a particular outcome of our game, we will express the result relative to the order in which the players toss their coins. For example, the permutation a = [BDCA] refers to a situation in which n = 4 players toss in the order A, B, C, D, with B being the first to achieve a head, D the second, and so on. Note that this representation of a permutation is not at all the same as cycle notation (in which the above outcome would be written (124)). Rather, our representation is just the bottom row in the