F(2)= F(0)+ F(1) = F(1) = 1
F(3)= F(2)+ F(1) = F(1) + F(1) = 2
F(4)= F(3)+ F(2) = F(1) + F(1) + F(1) = 3
F(5)= F(3)+ F(2) = [F(1) + F(1) + F(1)] + [F(1) + F(1) ]= 5 * F(1) = 5
F(6)= F(5)+ F(4) = 5 * F(1) + 3 * F(1) = 8 * F(1) = 8
F(7)= F(6)+ F(5) = (8+5)*F(1) = 13 * F(1) = 13
F(8)= F(7)+ F(6) = (13+8) * F(1) = 21 * F(1) = 21


per l'ovvero ha solo portato tutto a primo menbro e messo in evidenza a^n-2...banale