The proof of Theorem 5
We are going to prove that the right side of (2) satisfy (1) of Definition 3 for p = 4q.
f(1)=1=F(1)F(2q)/F(2q).
f(2)=1=F(2)F(2q)/F(2q).
For k = 0,1,...,4q-3
f(4qn+k)+f(4qn+k+1) =(F(2qn+k)F(2qn+2q)+F(2qn+k+1)F(2qn+2q))/F(2q)
=(F(2qn+k+2)F(2qn+2q))/F(2q)=f(4qn+k+2) ...(3).
f(4qn+4q-2)+f(4qn+4q-1)= (F(2qn+4q-2)F(2qn+2q)+F(2qn+4q-1)F(2qn+2q))/F(2q)
=F(2qn+4q)F(2qn+2q)/F(2q)=f(4qn+4q) ...(4).
f(4qn+4q-1)+f(4qn+4q)=( F(2qn+4q-1)F(2qn+2q)+F(2qn+2q)F(2qn+4q))/F(2q)
=F(2qn+2q)F(2qn+4q+1)/F(2q) ...(5).
f(4qn+4q+1)=F(2qn+2q+1)F(2qn+4q)/F(2q) ...(6).
By using the well known formula
F(n-m)= F(m+1)F(n)-F(m)F(n+1)
we can get
F(2qn+2q)F(2qn+4q+1)+F(2q)=F(2qn+4q)F(2qn+2q+1) ...(7).
Therefore by (5), (6) and (7) f(4qn+4q-1)+f(4qn+4q)+1=f(4qn+4q+1) ...(8).
Therefore by (3), (4) and (8) the right side of (2) satisfy the condition of (1) of Definition 3,
and we can finish the proof.