title: Cron expression to schedule a job every two years
body: <p>I'm building a Quartz cron expression to schedule a job to run on a specific day every two years from today. I've tested quite a few but I think one of the following should do the work:</p>
  
  <pre><code>53 18 23 12 ? 2013/2 =&gt; starting on year 2013 and on every two years later on
  53 18 23 12 ? */2
  </code></pre>
  
  <p>But both of them fail the Quartz cron expression validation test. What could be the right cron expression?</p>