There is a 5×5 grid in front of you. You have to fill 25 squares with only 0 and 1.
But, every pair of neighboring squares (that is not diagonally adjacent) needs to have a product equal to 0.
How many possible grids are there?
(In reply to
computer solution by Charlie)
I notice the bottom right corner never has a 1 in Charlie's 37 examples. Could the program have retraced back before trying to put a "1" in this spot?
Yes, that's it - if I don't count the ones with a 1 in the corner I only get 37869 like Charlie.
Edited on April 30, 2019, 2:36 am
One more thought.....
