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14304Re: Prime generator

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  • jim_fougeron
    Dec 31, 2003
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      --- In primenumbers@yahoogroups.com, "Hadley, Thomas H (Tom), ALABS"
      <thadley@a...> wrote:
      > Cary,
      >
      > Jud is right. If my calculations are correct, the number of primes
      > between 2*10^19 and 3*10^19 is about 2*10^17. If a program could
      > generate
      > a million primes per second, it would still take 2*10^11 seconds,
      or
      > 6000 years to generate them -- and a lot of storage.
      >
      > Jud, what is the program you would use to generate a string of
      > consecutive 20-digit primes if you wanted say, 1000 or so of them?

      I would use PFGW. Simply run this file:

      ABC2 10^20+$a
      a: from 1 to 100000 step 2

      The results of that (on my Athlon 750 took 20 seconds, and 2147 prp's
      were generated. (note stdout and stderr were redirected to nul)

      If you wanted 200000 primes (prp's), then I would recommend using
      a tool such as CPAPSieve (or NewPGen) prior to running PFGW.

      Jim.

      > Tom Hadley
      >
      > -----Original Message-----
      > From: Jud McCranie [mailto:j.mccranie@a...]
      > Sent: Wednesday, December 31, 2003 12:36 PM
      > To: Cary Walker
      > Cc: primenumbers@yahoogroups.com
      > Subject: Re: [PrimeNumbers] Prime generator
      >
      >
      > At 12:50 PM 12/31/2003, Cary Walker wrote:
      >
      > I'm afraid this is going to be a trivial question for you: I am
      looking
      > for
      > >a program that will generate all the primes from ~2x10^19 to some
      large
      > >upper bound. ...
      >
      > > Is there a program that will generate all the primes in a
      > >range?
      >
      > Yes, but if that is your lower bound, unless the upper bound isn't
      much
      > larger it will take too long to generate all of the primes or you
      will
      > run
      > out of space to store them.
      >
      >
      >
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