lychrel.rb

class Lychrel
  def initialize(starting_at:)
    @start = starting_at
  end

  def for(iterations:)
    last = start
    yield last

    iterations.times do
      last = last + last.to_s.reverse.to_i
      yield last
    end
  end

  private

  attr_reader :start
end

Lychrel.new(starting_at: 196).for(iterations: ARGV.first.to_i) do |num|
  puts num
end