title: Find the area of an n-interesting polygon
body: <p>Consider:</p>
  <p><a href="https://i.stack.imgur.com/s00Uy.png" rel="noreferrer"><img src="https://i.stack.imgur.com/s00Uy.png" alt="Enter image description here" /></a></p>
  <p>I am trying to find the area of an n-interesting polygon, where (n=1, A=1, n=2, A=5, n=3, A=13, n=4, A=25, and so on). So the formula for an n-interesting polygon is the area of an (n-1)-interesting polygon+(n-1)*4. When running the program, a hidden test shows that the code is wrong. What is wrong with my code?</p>
  <pre><code>def shapeArea(n):
      if n == 0:
          return 0
      if n == 1:
          return 1
      for i in range(2, n+1):
          return (shapeArea(n-1) + (n-1)*4)
  </code></pre>