Fibonacci sequence is defined by f(1)=1,f(2)=1 and f(m) =f(m-1)+f(m-2) i.e. 1, 1, 2, 3, 5, 8, 13, ...
Prove that for all composite values of n>4, f(n) is composite.

(In reply to Fibs and primes by broll)

1. Since your Email address is hidden I use this channel
to convey  some advice. Hope you don't mind.

2.  Reasoning OK, but for the sake of claritu  leave 
   paragraph 4.  with a. and b. only ,  so that 4c  will be par. 5.

3. Add paragraph 6., starting with : So we have proven ...etc

4. If you EDIT more than once , you may erase the previous remarks like "Edited..bla bla.." and leave only the last one.

Posted by Ady TZIDON on 2010-07-22 12:48:15