Arrangements and Combinations · Catalan Numbers: Introduction
Lesson 3
Problem. Consider a token on a grid that can move one step to the right or one step up per move. Let \(G(n)\) be the number of ways the token can move from point \((0,0)\) to point \((n,n)\) without going above the diagonal (i.e., the straight line from \((0,0)\) to \((n,n)\)). For example, \(G(3)=5\):
4 points