Here's a Ruby script to experiment with correlations that may be useful in developing a genetic (evolutionary) algorithm for factoring the product of two primes. The comments explain it:

#!/usr/bin/env ruby
# Let C = F1 * F2, where F1 and F2 are primes.
#
# This script gives a visual aid to help determine if the value of some function
# (specified by the user) on a test integer is correlated with the test
# integer's hamming distance from min(F1, F2).
#
# If such a correlation exists, it may be possible to use that function to
# calculate the 'fitness' of test integers in a genetic (evolutionary) algorithm
# for factoring C.
#
# Of course the function must be efficiently computable without knowing the
# factorization of C.
#
# Set the function by modifying the 'function' method below. Set the F1 and F2
# by modifying the 'F1' and 'F2' variables below. C is calculated from F1 and
# F2.
#
# Some interesting functions are:
#   - The hamming distance between C and the test integer.

# If you don't have the gnuplot gem, run `gem install gnuplot`
require 'gnuplot'

F1 = 8831
F2 = 12479

# Set this to true to make the multiplicity of points visible by adding random
# variations in their horizontal position.
JITTER = false

F_DESC = "HammingDistance(test, C)"
def function( composite, potentialFactor )
  hammingDistance( composite, potentialFactor )
end

# ----------------------------------------------------------------------------

def hammingDistance( a, b )
  (a ^ b).to_s( 2 ).count( "1" )
end

results = []

compareFactor = [F1, F2].min
composite = F1 * F2

1.upto( Math.sqrt( composite ).ceil * 4 ) do |i|
  results << [ function( composite, i ), hammingDistance( i, compareFactor ) ]
  puts i if i % 100_000 == 0
end

Gnuplot::open do |gp|
  Gnuplot::Plot.new( gp ) do |plot|
    plot.title "C = F1 * F2 where F1 and F2 are prime. \\n" +
                "C = #{F1 * F2}; F1 = #{F1}; F2 = #{F2}."
    plot.ylabel "HammingDistance(test, min(F1, F2))"
    plot.xlabel F_DESC
    plot.xrange "[0:]"
    plot.yrange "[0:]"

    x = results.map { |r| r[0] }
    y = results.map { |r| r[1] }

    if JITTER
      x = x.map { |v| v + rand() / 10 }
    end

    plot.data << Gnuplot::DataSet.new( [x, y] ) do |ds|
      ds.with = JITTER ? "dots" : "points"
      ds.notitle
    end

  end
end