关于“幸运数”的计数问题

摘要

如果正整数b的各位数字之积等于正整数a，则称b为a的幸运数。本文证明了幸运数存在性定理，并归纳得到了关于幸运数计数问题的两个命题。%If the product of each number in positive integer b equals a positive integer a, then b is called a’ s lucky number .In this paper the existence theorem of lucky number is proved and two propositions are induced from the counting problem of lucky numbers .