Chris Angelico's suggestion:
>>> bitcount = bytes(bin(i).count("1") for i in range(256))
>>> t = Timer('sum(number.to_bytes((number.bit_length() + 7) // 8,'
... '"little").translate(bitcount))',
... setup='from __main__ import bitcount; number=2**10001-1')
>>> min(t.repeat(number=10000, repeat=7))-- http://mail.python.org/mailman/listinfo/python-list
