Take the number and multiply it by each of , , and :
By concatenating each product we get the to pandigital, . We will call the concatenated product of and .
The same can be achieved by starting with and multiplying by , , , , and , giving the pandigital, , which is the concatenated product of and .
What is the largest to pandigital -digit number that can be formed as the concatenated product of an integer with where ?
Write-up coming later
The complete problem is available here. An approach, code, and answer will be added later.