## possible software bugs

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• Hi, I have started using CPAPSieve to count the number of primes in 10^8th blocks after powers of 10. The version I downloaded is from 9/29/2001. It is
Message 1 of 2 , Apr 3, 2003
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Hi,

I have started using CPAPSieve to count the number of primes in
10^8th blocks after powers of 10. The version I downloaded is from
9/29/2001. It is blazingly fast, but seems to overstate the count by
1. e.g. pi(10^23+10^8)-pi(10^23)= 1886441. When I sieve past the
square root, it still saves 1886442 values. I have looked at other
ranges with the same plus 1 result. Is there a newer version? How
can I process the output file to be human readable so I can find the
extra "prime"? Is there something else available that is better for
sieveing these contiguous blocks?

I was using the Factwin program, which I got from the Prime Pages.
When I entered the prime 8999999999999999983, it gave me the factors
3272003 and 2750608724992. These produce 8999999999999998976 and are
obviously not prime themselves. The biggest number it would accept
was 1 less than 9*10^18 rather than 2^63. Is there a more recent
working version or something better?

Finally, I am using fastpix to try to zero in on nth primes, like the
2 trillionth one (I think it is 61427839512211). It requires big
steps for big powers of 10. I can get it to do a step that is about
100 millionth of my x, but unless I get lucky, that can leave me
quite a ways away form my goal. Is there something comparable with
finer resolution? In the printout, I understand x and pi(x), but
what are y, z, A, B, C, D, phi0 and Sigma?

Best regards,

David Baugh
• Type CPAPSieve -? to see a list of options. There is a -L option, which writes the file out as a human readable file (an input file for PFGW). Simply use
Message 2 of 2 , Apr 4, 2003
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Type CPAPSieve -? to see a list of options.

There is a -L option, which writes the file out as a "human" readable
file (an input file for PFGW). Simply use (for file input file 10x23)
CPAPSieve -I=10x23 -O=10x23.input -L -Mp=3
Do this after you have trial factored and want to save to readable
file.

If starting from "scratch", then simply do
CPAPSieve -O=10x26 -b=10 -e=26 -k=1 -K=100000001 -Mp=10000000100000 -L
and the program would save data out in that format to start with.

Note, as you move forward, trial factoring to sqrt(N) will become
very time consuming. I would recommend trial factoring a much lower
level, then running the results through PFGW to pull the primes out
of the composites.

Jim.

--- In primenumbers@yahoogroups.com, "pbtoau" <PbtoAu@A...> wrote:
> Hi,
>
> I have started using CPAPSieve to count the number of primes in
> 10^8th blocks after powers of 10. The version I downloaded is from
> 9/29/2001. It is blazingly fast, but seems to overstate the count
by
> 1. e.g. pi(10^23+10^8)-pi(10^23)= 1886441. When I sieve past the
> square root, it still saves 1886442 values. I have looked at other
> ranges with the same plus 1 result. Is there a newer version? How
> can I process the output file to be human readable so I can find
the
> extra "prime"? Is there something else available that is better
for
> sieveing these contiguous blocks?
>
> I was using the Factwin program, which I got from the Prime Pages.
> When I entered the prime 8999999999999999983, it gave me the
factors
> 3272003 and 2750608724992. These produce 8999999999999998976 and
are
> obviously not prime themselves. The biggest number it would accept
> was 1 less than 9*10^18 rather than 2^63. Is there a more recent
> working version or something better?
>
> Finally, I am using fastpix to try to zero in on nth primes, like
the
> 2 trillionth one (I think it is 61427839512211). It requires big
> steps for big powers of 10. I can get it to do a step that is