2023 Fall LMT Team #13 16 coins heads up in a 4x4 grid
Source:
February 4, 2024
combinatorics
Problem Statement
Ella lays out coins heads up in a grid as shown.
https://cdn.artofproblemsolving.com/attachments/3/3/a728be9c51b27f442109cc8613ef50d61182a0.png
On a move, Ella can flip all the coins in any row, column, or diagonal (including small diagonals such as & ). If rotations are considered distinct, how many distinct grids of coins can she create in a finite number of moves?