prime_number.rb

class PrimeNumber
  def initialize
    print 'Enter number: '
    @num = gets.to_i
    @primes = []
  end

  def generate
    for i in (2..(@num**2)) do
      for j in (2..i) do
        break if i%j == 0
      end
      @primes << i if i.eql?(j)
      break if @primes.length.eql?(@num)
    end
  end

  def display
    for i in (0..@num-1) do
      for j in (0..@num-1) do
        print "#{@primes[i]+@primes[j]} "
      end
      puts
    end
  end
end

p = PrimeNumber.new
p.generate
p.display