def synapsesvsM(s_ = 25):
  # Compute number of synapses on a segment as a function of M
  listofMValues = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
                   18, 19]
  listofSynapses = []
  n_=1000
  print "\n\nn=%d, s=%d" % (n_,s_)
  for M_ in listofMValues:
    numSynapsesAfterUnion = numOnBits.subs(n,n_).subs(s,s_).subs(M,M_).evalf()
    listofSynapses.append(numSynapsesAfterUnion)

  print listofSynapses