p.rb

#!/usr/bin/env ruby
# Modifying Float and Integer for fun.
class Float
  def whole?
    n = self
    !!( n % 1 == 0 )
  end
end

class Integer
  def prime?
    n = self
    2.upto(n) do |i|
      div = n.to_f / i

      if div.whole?
        return !!(i == n)
      end
    end

    return false
  end

  def palindromic?
    n = self
    !!( n == n.to_s.reverse.to_i )
  end

  def palindromic_prime?
    self.palindromic? && self.prime?
  end
end

limit = 100

primes = []
2.upto(Float::INFINITY).lazy.each do |x|
    break if primes.length == limit

    primes.push(x) if x.palindromic_prime?
end

print primes