#!/usr/bin/env python def multdigits(D): answer = n = 1 start = 0 d = D.pop(0) - 1 while True: ns = str(n) end = start + len(ns) while start <= d < end: answer *= int(ns[d - start]) if not len(D): return answer d = D.pop(0) - 1 start = end n += 1 return answer print multdigits([10 ** e for e in range(7)])