Hello,

That's the sum of cubes

Well, well... The formula is

If you cant remember it, start from and develop it

Solving for it... ? Not impossible.

Note that

Since x and y are natural numbers, and are integers.

So the two factors will be a combination of the divisors of 208. For example 26 and 8 or 13 and 16 or...

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Try all the possible values for x+y among 1,2,4,8,13,16,26,52,104,208 ()

Then note that and is respectively among 208,104,...,2,1

Note that otherwise the product can't be large enough (check it )

If you need more explanations, do tell me. But as far as I can see, it will be a long way to do >.>