$\displaystyle M_{23}=2^{23}-1=8388607$
$\displaystyle \left \lfloor \sqrt{8388607} \right \rfloor=2896$
$\displaystyle 2kp+1=46k+1, \ 1\leq k \leq 62$
Since there are 62 possible values to check, how can this be done in a more efficient fashion?
$\displaystyle M_{23}=2^{23}-1=8388607$
$\displaystyle \left \lfloor \sqrt{8388607} \right \rfloor=2896$
$\displaystyle 2kp+1=46k+1, \ 1\leq k \leq 62$
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.