title: Find join point of two sequences
body: <p>I'm looking for an algorithm of a function that can return a point of the join of two sequences, for example:</p>
  
  <p><code>seq1=471 seq2=480</code></p>
  
  <p>However, </p>
  
  <pre><code>seq1=seq1+(4+7+1) =483
  
  seq1=seq1+(4+8+3) =498
  
   ....and so on. 
  </code></pre>
  
  <p>For the seq2 we do the same thing</p>
  
  <pre><code>seq2=seq2+(4+8+0) =492
  
   ....and so on.
  </code></pre>
  
  <p>We do that until we find the joining point, in our example the joining point is 519
  so the main aim of the function is returning 519.
  The function has 2 params (seq1,seq2) and returns an integer.</p>