def yanghui(n):
    i,temp = 1,[]
    while i <= n:
        a=[1]
        if i == 1:
            temp=a
            yield a
        else:
            a=[1]
            for k,v in enumerate(temp):
                if k<=(len(temp)-2):
                    a.append(v+temp[k+1])

            a.append(1)
            temp=a
            yield a
        i+=1