title: How to automatically generate sequent numbers when using a form
body: <p>Ahab stated in 2010: the complex looking number based on the Timestamp has one important property, the number can not change when rows are deleted or inserted.
  As long as the submitted data is not changed by inserting deleting rows the simple formula <code>=ArrayFormula(ROW(A2:A) - 1)</code> may be the easiest one to use. </p>
  
  <p>For other situations there is no nice reliable solution. :(</p>
  
  <p>Now we live in 2015. Maybe times have changed?</p>
  
  <p>I need a reliable way to number entries using a form.</p>
  
  <p>Maybe a script can do the trick? A script that can add 1 to each entry?
  That certain entry has to keep that number even when rows are deleted or inserted.</p>
  
  <p>I created this simple spreadsheet in which I added 1,2, and 3 manually,please have a look:
  <a href="https://docs.google.com/spreadsheets/d/1H9EXns8-7m9oLbCrTyIZhLKXk6TGxzWlO9pOvQSODYs/edit?usp=sharing" rel="nofollow">https://docs.google.com/spreadsheets/d/1H9EXns8-7m9oLbCrTyIZhLKXk6TGxzWlO9pOvQSODYs/edit?usp=sharing</a></p>
  
  <p>The script has to find the maximum of the former entries, which is 3, and then add 1 automatically.</p>
  
  <p>Who can help me with this?</p>
  
  <p>Grtz, Bij</p>