I have already posted my version here.
But it is not able to load yet.
It will be,
u_n is the Fibonacci numbers
Let a and b be odd positive integers.
Define the sequence f_n by putting f_1=a, f_2=b, and by letting f_n for n>2 be the greatest odd divisor of f_(n-1) + f_(n-2).
Show that f_n is constant for n sufficiently large and determine the eventual value as a function of a and b.
Thank you very much.