def yanghui(n):
		

		

			pre = [1]
		

		

			i = 1 
		

		

			while i <= n:
		

		

			if i == n:
		

		

			yield pre
		

		

			new_list = []
		

		

			i += 1 
		

		

			for j in range(i - 2):
		

		

			new_list.append(pre[j] + pre[j + 1])
		

		

			pre = [1] + new_list + [1]