A method for obtaining Fibonacci identities
  For the Lucas sequence $\{U_{k}(P,Q)\}$ we discuss the identities such as the well-known Fibonacci identities. We also propose a method for obtaining identities involving recurrence sequences. With the help of which we find an interpolating type identity for second order linear recurrences. 
Dmitry I. Khomovsky
math.NT cs.IT math.IT math.NA math.RA