king in 7x7 chessboard (IV Soros Olympiad 1997-98 Correspondence 10.5)
Source:
June 1, 2024
combinatoricscombinatorial geometry
Problem Statement
In the lower left corner of the square board there is a king. In one move, he can move either one cell to the right, or one cell up, or one cell diagonally - to the right and up. How many different ways can the king get to the upper right corner of the board if he is prohibited from visiting the central square?