title: Select nth child select 1, 2, 5, 6, 9, 10 etc
body: <p>I have a set of divs as follows,</p>
  
  <pre><code>&lt;div class="selector"&gt;
      &lt;div&gt;1&lt;/div&gt;
      &lt;div&gt;2&lt;/div&gt;
      &lt;div&gt;3&lt;/div&gt;
      &lt;div&gt;4&lt;/div&gt;
      &lt;div&gt;5&lt;/div&gt;
      &lt;div&gt;6&lt;/div&gt;
      &lt;div&gt;7&lt;/div&gt;
      &lt;div&gt;8&lt;/div&gt;
      &lt;div&gt;9&lt;/div&gt;
      &lt;div&gt;10&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to provide background colour to divs 1,2,5,6,9,10 etc. How do I select the particular divs using nth selector? Is it possible?</p>
  
  <p>PS: The number of divs may grow to n.</p>