title: Can't figure out how to increment a variable within a recursive function
body: <p>I am trying to create a python script for the collatz conjecture (if a number's odd, times it by three and add 1, and if it's even, divide by two). I can't figure out how to successfully increment a variable that shows how many iterations of the function and I think it has something to do with it being recursive. Here's what I've got so far:</p>
  
  <pre><code>def collatz(n):
      list_terminate = [0, 1, 2, 4]
      if n in list_terminate:
          return n
      else:
          if n % 2 == 0:
              print(n)
              iterations += 1
              return collatz(n // 2)
          if n % 2 == 1:  
              iterations += 1
              print(n)
              return collatz((n * 3) + 1)
  </code></pre>