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Math Help - Determine whether M_{23} is prime

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    Determine whether M_{23} is prime

    M_{23}=2^{23}-1=8388607

    \left \lfloor \sqrt{8388607} \right \rfloor=2896

    2kp+1=46k+1, \ 1\leq k \leq 62

    Since there are 62 possible values to check, how can this be done in a more efficient fashion?
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    Quote Originally Posted by dwsmith View Post
    M_{23}=2^{23}-1=8388607

    \left \lfloor \sqrt{8388607} \right \rfloor=2896

    2kp+1=46k+1, \ 1\leq k \leq 62

    Since there are 62 possible values to check, how can this be done in a more efficient fashion?
    Does this help? Lucas–Lehmer primality test

    Edit: The MathWorld page is a bit cleaner than the Wikipedia article at the moment, in my opinion.
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