http://projecteuler.net/problem=32 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.