n=4的一些解
..4....4....1....6....4....6....4....4....6....1....6....6....4....1....6....6
..6....2....3....3....5....2....2....6....4....5....2....3....5....5....2....3
..4....6....6....6....1....1....6....5....2....3....1....5....1....2....6....5
..1....3....5....5....2....6....2....6....6....5....5....4....4....1....1....1