The Collaborative International Dictionary of English v.0.48:

Successiveness \Suc*ces"sive*ness\, n.
   The quality or state of being successive.
   [1913 Webster]

WordNet (r) 3.0 (2006):

successiveness
    n 1: a following of one thing after another in time; "the doctor
         saw a sequence of patients" [syn: sequence,
         chronological sequence, succession, successiveness,
         chronological succession]