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Re: Percentage of Primes

  • To: mathgroup at smc.vnet.net
  • Subject: [mg128192] Re: Percentage of Primes
  • From: Bob Hanlon <hanlonr357 at gmail.com>
  • Date: Sun, 23 Sep 2012 02:58:52 -0400 (EDT)
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  • References: <20120922064747.0DFD4685F@smc.vnet.net>

Minimalist approach:

ListPlot[
 Count[Range[#], _?PrimeQ]/# & /@
  Range[1000]]

With bells and whistles:

Manipulate[
 Module[{data, pt},
  data = Count[Range[#], _?PrimeQ]/# & /@
    Range[nmax];
  pt = {nmax, data[[-1]]};
  ListPlot[
   data,
   Frame -> True,
   Axes -> False,
   PlotRange -> {-0.02, 0.7},
   MaxPlotPoints -> 150,
   PlotStyle -> Darker[Red],
   Epilog -> {Blue, AbsolutePointSize[2],
     Point[pt],
     Text[
      NumberForm[N[data[[-1]]], {4, 3}],
      pt, {1, 2}]}]],
 {nmax, 25, 1000, 25,
  Appearance -> "Labeled"}]


Bob Hanlon


On Sat, Sep 22, 2012 at 2:47 AM, Jared E <eggers.jared at gmail.com> wrote:
> I'm brand new to Mathematica, so there's only so much I can teach myself by playing around with it.  Could somebody give me some sample code for displaying a graph of the percentage of primes from, say, 1 to 1000.  The x-ax is would be the integers from 1 to 1000 and the y-axis would indicate the density of primes from 1 to n.  I can then figure out how to apply this code to other types of problems.  Thanks, Jared
>



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