Fmdn[x_, rho_, n_] :=
Module[{i=0, j=0, v=0, V},
  V=Mdn[n-1, rho, n];
  If[x == 0.,
      Plus @@ V,
      Sum[(Plus @@ Take[V,i+1]) *
	  (Sum[(((rho n) (v-x))^(v n + n - 1 - i))/(v n + n - 1 - i)! E^(-(rho n) (v-x)),
	  {v,0,Floor[x]}]), {i,0,n-1}]
  ]
]