[]
>>> rep_digits(6)
[6]
>>> rep_digits(7)
[1, 4, 2, 8, 5, 7]
>>> rep_digits(8)
[]
>>> rep_digits(9)
[1]
>>> rep_digits(10)
[]
"""
digit_list = []
seen_pairs = set()
order = base
while True:
digit, rem = pair = divmod(order, n)
if pair == (0, 0):
return [] # Exact division, no repeating digits.
# Check if we've seen this digit and remainder before. If so, we've
# found the repetition, so return.
if pair in seen_pairs:
i = digit_list.index(pair)
return [d for d, r in digit_list[i:]]
# Mark the digit as seen, and go to the next higher order.
seen_pairs.add(pair)
digit_list.append(pair)
order = rem * base
print(max_key((n, len(rep_digits(n))) for n in range(1, 1000)))
