My backwards logic
davea at davea.name
Sat Sep 6 05:10:40 CEST 2014
Seymore4Head <Seymore4Head at Hotmail.invalid> Wrote in message:
> On Fri, 05 Sep 2014 12:48:56 -0400, Seymore4Head
> <Seymore4Head at Hotmail.invalid> wrote:
> If you start with the list [3,5,7] and step through the list of all
> remaining odd numbers (step 2), and start appending numbers that won't
> divide by numbers already appended in the list, that would seem like a
> pretty efficient way to find all prime numbers.
Yes, that's a well known optimization. In addition, you can stop
once you reach the square root of the target. No point in
dividing by the higher numbers in the list, since if the result
comes out even, you'd have already exited the loop.
More information about the Python-list