Problem 491
Double pandigital number divisible by 11
We call a positive integer double pandigital if it uses all the digits 0 to 9 exactly twice (with no leading zero). For example, 40561817703823564929 is one such number.
How many double pandigital numbers are divisible by 11?
能被11整除的二重复全数字数
我们称一个正整数是二重复全数字的,如果它使用0~9这十个数字恰好各两次(没有前导0)。例如,40561817703823564929就是一个二重复全数字数。
有多少个能被11整除的二重复全数字数?