n=4的一些解
..1....2....4....1....2....1....2....1....4....1....3....1....3....1....1....3
..1....2....2....1....3....2....2....1....3....1....4....3....2....4....1....4
..1....3....1....3....3....2....2....3....2....4....2....2....1....3....2....1
..4....1....1....2....1....4....1....4....1....3....1....2....1....2....2....1