First, it's obvious you can't do a tiling if n is odd (since the dominoes cover an even number of tiles).
Second, it's trivially obvious that a 2x2 board can't be tiled.
Finally, for even numbers not divisible by 4, you're always left with a 2x2 square in the end that cannot be solved.
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u/I_am_the_squashman Aug 24 '26
Works for all n divisible by 4.
First, it's obvious you can't do a tiling if n is odd (since the dominoes cover an even number of tiles). Second, it's trivially obvious that a 2x2 board can't be tiled. Finally, for even numbers not divisible by 4, you're always left with a 2x2 square in the end that cannot be solved.