There must be a better way to compute this...

heads.py

import random

random.seed()

def flip():
  return random.choice([True, False])

def run():
  b = flip()
  n = 1
  while True:
    (a, b) = (b, flip())
    n += 1
    if a and b:
      return n

runs = 100000
def count():
  counts = [0] * 100
  for i in xrange(0, runs):
    n = run()
    if n < len(counts):
      counts[n] += 1
  return counts

counts = count()
for n in range(2,10):
  print round(float(counts[n]) / runs * 2**n)