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Definition Let
be the unique integer (with respect to a fixed
) such that


Conjecture A natural number
is a prime iff
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![$$ \displaystyle \sum_{i=1}^{\left \lfloor \frac{\sqrt[3]p}{2} \right \rfloor} r_i = \left \lfloor \frac{\sqrt[3]p}{2} \right \rfloor $$](/files/tex/99af565f4cc4d3bab11eb3fbf54f78626678d484.png)
The conjecture is obviously true when is prime, so it suffices to check when
is composite.
Bibliography
* indicates original appearance(s) of problem.