title: How do you make a regex to select a pattern of X, Y or Z length
body: <p>If I need to find a regex that matches any positive number of lower case characters, an <code>N</code>, and then either 6 integers, 8 integers or 15 integers. But not match any other number of intagers</p>
  
  <p>e.g. "abcN123456" or "abcdN12345678" or "abN123456789012345" or "abcdefgN123456"</p>
  
  <p>How would you make a regex that finds this?</p>
  
  <p>It starts with <code>[a-z]+N</code> but don't know how to do the variable number of integers</p>