- or download this
F(n+m) = F(n)F(m-1) + F(n-1)F(m+1)
- or download this
F(2n) = F(n)F(n-1) + F(n-1)F(n+1)
= F(n)F(n-1) + F(n-1)(F(n) + F(n-1))
= 2F(n)F(n-1) + F(n-1)F(n-1)
- or download this
F(2n-1) = F(n-1)F(n-1) + F(n-2)F(n)
= F(n-1)F(n-1) + (F(n)-F(n-1))F(n)
= F(n)F(n) - F(n-1)F(n) + F(n-1)F(n-1)