title: Continuous nth-child (multiple occurrences)
body: <p>I have a list made of thousands of items.</p>
  
  <p>In order to display them in a clean fashion, I need to apply a specific css rule to every third item of the list (3th li, 6th li, 9th li,....,3000th li..9999th li...).</p>
  
  <p>Normally, I would use this:</p>
  
  <pre><code>li:nth-child(3),li:nth-child(6),...
  </code></pre>
  
  <p>but this would obviously be too tedious to write a css rule for each item (not to mention that the list may grow over time)</p>
  
  <p>I also may use a class for every third item of the list but the list is reordered constantly according to a filter by a jQuery plugin (Quicksand), so the 6th li can asynchronously become the 4th one according to the user manipulation.</p>
  
  <p>So, is there a way to use a css rule that would simply do something like this?:</p>
  
  <pre><code>li:nth-child(n*3)
  </code></pre>
  
  <p>Thank you.</p>