title: Python Persistent number
body: <p>need some assistance to write a Persistent number program in Python to determine the smallest non-negative integer with a persistence
  (715 ---> 35 ---> 15 ---> 5) of 3, then 4, then 5, then 6, then 7. With an output with the following format:</p>
  
  <pre><code>The smallest integer with a persistence of 3 is: 39
  The smallest integer with a persistence of 4 is: xx
  The smallest integer with a persistence of 5 is: xxx
  The smallest integer with a persistence of 6 is: xxxx
  The smallest integer with a persistence of 7 is: xxxxx
  </code></pre>
  
  <p>Any code links or leads would be appreciated, thanks. </p>