counting paths in a triangular grid, moves only to one direction
Source: Mexican Mathematical Olympiad 1990 OMM P1
July 29, 2018
combinatoricsgridpaths
Problem Statement
How many paths are there from to the line if the path does not go through any vertex twice and always moves to the left?
https://cdn.artofproblemsolving.com/attachments/e/6/a4bc3a9decc06eaeed6f7e99cb58f7b2524471.jpg