MathDB
no of paths in a triangular grid

Source: Mexican Mathematical Olympiad 1989 OMM P6

July 27, 2018
combinatoricsgrid

Problem Statement

Determine the number of paths from AA to BB on the picture that go along gridlines only, do not pass through any point twice, and never go upwards? https://cdn.artofproblemsolving.com/attachments/0/2/87868e24a48a2e130fb5039daeb85af42f4b9d.png