title: Deleting every 3rd and 5th line, but not the 15th in sed
body: <p>I am trying to look for a way to delete every 3rd and 5th line but not the 15th using sed, but this is the thing: you can't make use of the ~ way (GNU). It has to be something like </p>
  
  <pre><code>sed 'n;n;d' test
  </code></pre>
  
  <p>but I can't figure out how to combine the 3...</p>
  
  <p>Example input</p>
  
  <pre><code>1
  2
  3
  4
  5
  6
  7
  8
  9
  10
  11
  12
  13
  14
  15
  </code></pre>
  
  <p>Example output:</p>
  
  <pre><code>1
  2
  4
  7
  8
  11
  13
  14
  15
  </code></pre>
  
  <p>It'll need to be in sed, no awk or perl</p>