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Re: [PrimeNumbers] strange news

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  • Phil Carmody
    ... Strange is indeed the word. This is quite an interesting case. His claim about the production of prime numbers and only prime numbers using his formula
    Message 1 of 6 , Nov 8, 2008
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      --- On Sat, 11/8/08, amin B <aminb_6829@...> wrote:
      > Hello friends
      > Being shocked when I have heard such this amazing news
      > that an Iranian professor named  MR Moosavi  has
      > explored the prime numbers formula .For more information and
      > viewing the formula visit the following site:
      >
      > http://www.primenumbersformula.com/
      >
      > I guess this claim based on finding the prime numbers
      > formula is just a lie since none valuated source talks about
      > so.And this event  just announced by Iran news.
      > Please leave your opinions about it.

      "Strange" is indeed the word. This is quite an interesting case. His claim about the production of prime numbers and only prime numbers using his formula is indeed correct, it's not one I've seen before, and it's remarkably simple, in particular it doesn't involve multiply-nested sums. So from the outset, it's worth a little bit of investigation.

      The function in question is:

      H(m) = 2 * ((2m+1)/2) ^ floor(((2m+1)/((2m)!+1))*floor(((2m)!+1)/(2m+1)))

      It took me about 2 minutes to work out how and why it works, and it might be fun for the easily amused to also cut their teeth on working it out themselves. There are a few clues on the above webpage, if you can't get it immediately. Here are also some spoilers ....



      s
      f
      p t
      o s
      o h
      l p
      i i
      l a
      l s
      o c
      e
      w e
      r

      s


      Perform a change of variable n = 2m+1 to get H as a function of n.


      f
      s
      u f
      p
      r o
      o
      t l
      i
      h l
      l
      e o
      e
      r w
      r
      s


      Look only at the value of the exponent, and ignore what is being raised to that power.


      d
      y
      o n
      o a
      e m
      u n
      e o
      y
      d r

      e

      ?


      We know for natural numbers a,b, (a/b)*(b/a) is always 1. However, when is (a/b)*floor(b/a) not equal to 1? (Assume a>=b for simplicity.)



      That should be enough, I hope. If not, you did notice Wilson's Theorem being mentioned on the webpage, I trust?

      In essense, the formula's very close to

      h(n) = p^(prime_p(p))

      Which would be p^1 = p for prime p, and p^0 = 1 for composite p.
      In order to not generate all those 1s, he's tweaked it to be

      h'(n) = 2*(p/2)^(prime_p(p))

      Phil
    • Alex Petty
      is this for real? -alex ... -- alexander.petty@gmail.com cell: +001.540.272.7970 skype: alex.petty [Non-text portions of this message have been removed]
      Message 2 of 6 , Nov 8, 2008
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        is this for real?

        -alex

        amin B wrote:
        >
        > Hello friends
        > Being shocked when I have heard such this amazing news that an
        > Iranian professor named MR Moosavi has explored the prime numbers
        > formula .For more information and viewing the formula visit the
        > following site:
        >
        > http://www.primenumbersformula.com/ <http://www.primenumbersformula.com/>
        >
        > I guess this claim based on finding the prime numbers formula is just
        > a lie since none valuated source talks about so.And this event just
        > announced by Iran news.
        > Please leave your opinions about it.
        >
        > [Non-text portions of this message have been removed]
        >
        >


        --
        alexander.petty@...
        cell: +001.540.272.7970
        skype: alex.petty



        [Non-text portions of this message have been removed]
      • Phil Carmody
        ... Please don t top-post. This , as a demonstrative pronoun, refers to prior context, yet you ve placed the context after it. ... And now to address your
        Message 3 of 6 , Nov 8, 2008
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          --- On Sat, 11/8/08, Alex Petty <alexander.petty@...> wrote:
          > is this for real?

          Please don't top-post. "This", as a demonstrative pronoun, refers to prior context, yet you've placed the context after it.

          > amin B wrote:
          > > Hello friends
          > > Being shocked when I have heard such this amazing news
          > > that an Iranian professor named MR Moosavi has explored the
          > > prime numbers formula.
          > >
          > > http://www.primenumbersformula.com/

          And now to address your actual question - "is this for real?".

          Yes, that mail really was sent to the mailing list.
          Yes, that website really does exist.
          Yes, that website does, as mentioned in the mail, really contain information about a prime number-related formula.

          If that doesn't adequately answer your question, perhaps you'd like to ask a slightly less nebulous one.

          Phil
        • Alex Petty
          let me ask again. is this a real discovery? i didn t follow the previous explanation. thanks, alex -- alexander.petty@gmail.com cell: +001.540.272.7970 skype:
          Message 4 of 6 , Nov 8, 2008
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            let me ask again.
            is this a real discovery? i didn't follow the previous explanation.

            thanks,
            alex


            --
            alexander.petty@...
            cell: +001.540.272.7970
            skype: alex.petty



            Phil Carmody wrote:
            >
            > --- On Sat, 11/8/08, Alex Petty <alexander.petty@...
            > <mailto:alexander.petty%40gmail.com>> wrote:
            > > is this for real?
            >
            > Please don't top-post. "This", as a demonstrative pronoun, refers to
            > prior context, yet you've placed the context after it.
            >
            > > amin B wrote:
            > > > Hello friends
            > > > Being shocked when I have heard such this amazing news
            > > > that an Iranian professor named MR Moosavi has explored the
            > > > prime numbers formula.
            > > >
            > > > http://www.primenumbersformula.com/
            > <http://www.primenumbersformula.com/>
            >
            > And now to address your actual question - "is this for real?".
            >
            > Yes, that mail really was sent to the mailing list.
            > Yes, that website really does exist.
            > Yes, that website does, as mentioned in the mail, really contain
            > information about a prime number-related formula.
            >
            > If that doesn't adequately answer your question, perhaps you'd like to
            > ask a slightly less nebulous one.
            >
            > Phil
            >
            >
          • Jens Kruse Andersen
            ... It depends what you mean by real. It works correctly and he may be the first to publish this particular formula, but useless prime formulas based on
            Message 5 of 6 , Nov 8, 2008
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              Alex Petty wrote:
              > let me ask again.
              > is this a real discovery? i didn't follow the previous explanation.

              It depends what you mean by real. It works correctly and he may be the first
              to publish this particular formula, but useless prime formulas based on
              Wilson's theorem are common.
              The discoverer added mention of it to Wikipedia in June 2007.
              I removed it with an edit summary pointing to Wikipedia policies and ending
              "Looks trivial, useless, non-notable":
              http://en.wikipedia.org/w/index.php?title=Formula_for_primes&diff=next&oldid=136831799

              At the time I checked that the formula actually works.
              It uses the well-known Wilson's theorem (apparently first discovered by the
              Arabian mathematician Ibn al-Haytham around year 1000) to test whether 2m+1
              is an odd prime. If it is then 2m+1 is produced, otherwise 2. Instead of
              writing this as a simple if-then-else, it uses a complicated formula with
              the floor function to avoid direct use of an if-then-else construct which is
              sometimes not considered an allowed part of a "formula".

              --
              Jens Kruse Andersen
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