title: How to navigate through a non recombinant binomial tree
body: <p>im looking to see how i can navigate through a non-recombinant binomial tree.
  I have set up my tree as following:
  <a href="https://i.stack.imgur.com/qbdTM.jpg" rel="nofollow noreferrer">enter image description here</a></p>
  <pre><code>def arbolno(t,S0,u,d):
  S=[S0]
  for i in range(1,2**(t+1)-1):
      if i%2==0:
          S.append(np.round(S[int(i/2-1)]*u,3))
      elif i%2!=0:
          S.append(np.round(S[int((i-1)/2)]*d,3)) 
  return S
  </code></pre>
  <p>Now, I want to calculate a return from a holding period, lets say, n moments.
  How can I index correctly, given my format of listing my nodes? For instance, if I define a return period of 2 moments in time, then, for instance, node number 14 would be compared with node 2.
  I want to know a general formula if there is, in order to index through my list of nodes correctly.
  Thanks!</p>