"""Show authpath indices for idx=6 and a=3."""

a = 3 # Number of levels
idx = 6 # leaf index
authpath = [0] * a
authpath[0] = idx ^ 1
for i in range(1, a):
    idx = idx // 2
    authpath[i] = idx ^ 1
print(authpath)  # [7, 2, 0]