title: How can I unfold the recurrence: T(n)=2T((n+2)/3)
body: <p>I'm trying to solve this recurrence, but I don't know how to unfold it.</p>
  
  <pre><code>T(n)=2T((n+2)/3) + 1
  </code></pre>
  
  <p>Can I ignore that "+2" and solve it as it was 2T(n/3) + 1?</p>
  
  <p>This comes from  a from a problem that uses a <code>V[a..b]</code> array and makes this return:</p>
  
  <pre><code>return V(X) + f(V, a, Y) + f(V, Z, b)
  </code></pre>
  
  <p>Where <code>Y</code> is <code>(2a+b)/3 and Z is (a+2b)/3</code></p>
  
  <p>So: <code>((b-a+3)/3) = ((n+2)/3)</code></p>