Another Hanukkah Miracle: The Gaps Between Consecutive   Christmas-in-Hanukkah Years is ALWAYS a Fibonacci Number!
  The Hebrew Calendar is based on very deep and complicated mathematics, involving diophantine approximation, but it is very surprising that the gaps between consecutive Christmas-in-Hanukkah years is always a member of the set {2,3,5,8}. This second edition, with new co-author Lisa Budd gives the answer to the question in the title. 
Lisa Budd and Shalosh B. Ekhad
math.HO