Please read my posts above.Zak hat geschrieben: You need give me an example to confirming your statement, otherwise mine is true and followed from Diophantine equations.
And you are making a big non-formal fallacy here. Even if I don't have a concrete example (I have, d=e=1, f=4), it does not mean that you are correct. It is like if you have a bogus proof of the Goldbach conjecture, I say that you are wroing, you ask me for a counter example of an even number impossible to be written as a sum of two primes, of course I cannot provide an example, but that does not make your "proof" correct.
You may want to learn above what a mathematical proof is.