MathDB

M2647

Part of Kvant 2021

Problems(1)

Parity differs from lines to diagonals

Source: Kvant Magazine No. 4 2021 M2647

3/9/2023
For which natural numbers nn{} it is possible to mark several cells of an n×nn\times n board in such a way that there are an even number of marked cells in all rows and columns, and an odd number on all diagonals whose length is more than one cell?
Proposed by S. Berlov
combinatoricsKvant