Some solutions for n=4
..2..0..1..0..0....3..0..0..0..0....4..0..0..0..0....0..4..0..0..0
..0..3..1..0..3....0..2..1..4..1....0..4..4..0..0....2..0..1..4..0
..0..3..4..0..3....0..3..0..0..1....0..4..3..0..0....0..1..2..0..0
..2..2..1..2..2....0..2..3..2..3....0..0..3..3..4....0..2..1..3..4
..0..0..4..4..4....0..0..0..2..0....0..0..0..1..4....0..0..4..2..1
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