  Quintessential inflation--in which a single scalar field plays the role of
the inflaton and quintessence--from a sum of exponentials potential V = A
(exp{5 phi}+exp{sqrt{2} phi}) or V = A (exp{5 phi}+exp{phi}) or a cosh
potential V = 2A cosh(5 phi) is considered in the context of five-dimensional
gravitation with standard model particles confined to our 3-brane. Reheating is
accomplished via gravitational particle production and the universe undergoes a
transition from primordial inflation to radiation domination well before big
bang nucleosynthesis. The transition to an accelerating universe due to
quintessence occurs near z = 1, as in LambdaCDM.
  Braneworld quintessential inflation can occur for potentials with or without
a minimum, and with or without eternal acceleration and an event horizon. The
low z behavior of the equation of state parameter w_phi provides a clear
observable signal distinguishing quintessence from a cosmological constant.
