Pandigital products
We shall say that an n-digit number is pandigital if it makes use of all
the digits 1 to n exactly once; for example, the 5-digit number, 15234,
is 1 through 5 pandigital.

The product 7254 is unusual, as the identity, 39  186 = 7254, containing
multiplicand, multiplier, and product is 1 through 9 pandigital.

Find the sum of all products whose multiplicand/multiplier/product
identity can be written as a 1 through 9 pandigital.

HINT: Some products can be obtained in more than one way so be sure to
only include it once in your sum.