n=4的一些解决方案:
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..2
..0..2..0..0..3..0....1..0..1..1..0..1....2..2..0..2..2..0....0..3..3..0..3..3
..0..0..2..0..0..3....2..2..1..2..2..1....3..0..0..1..0..0....0..1..0..0..1..0
..0..1..1..0..1..1....0..1..1..0..1..1....0..3..0..0..1..0....0..0..1..0..0..1
..0..2..0..0..2..0....1..0..1..1..0..1....2..2..0..2..2..0....0..3..3..0..3..3
..0..0..2..0..0..2....2..2..1..2..2..1....1..0..0..3..0..0....0..2..0..0..1..0