Determine whether M_{23} is prime

Printable View

July 20th 2010, 01:21 PM
dwsmith

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?
July 20th 2010, 01:30 PM
undefined

Quote:

Originally Posted by dwsmith

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

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

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

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.

All times are GMT -8. The time now is 02:17 AM.

Copyright © 2005-2013 Math Help Forum. All rights reserved.

Copyright © 2005-2013 Math Help Forum. All rights reserved.