Your question is not clear. First of all, 1729 is the smallest number that can be expressed as the sum of two positive cubes intwodifferent ways. So, are you looking to replace the number two with, say, 3, 4, ..., 9999? Or are you looking to remove the word "smallest" and just find all numbers < 10000 that are expressible as the sum of two positive cubes in two different ways?

Relevant link: Taxicab number - Wikipedia, the free encyclopedia