def bernoulli2():
    A, m = [], 0
    while True:
        A.append(Fr(1, m+1))
        for j in range(m, 0, -1):
          A[j-1] = j*(A[j-1] - A[j])
        yield A[0] # (which is Bm)
        m += 1

bn2 = [ix for ix in zip(range(61), bernoulli2())]
bn2 = [(i, b) for i,b in bn2 if b]
width = max(len(str(b.numerator)) for i,b in bn2)
for i,b in bn2:
    print('B(%2i) = %*i/%i' % (i, width, b.numerator, b.denominator))