∑i=1n=Fibn+2×(n−1)−Fibn+1+2 \sum\nolimits_{i=1}^{n} = Fib_{n+2} \times (n-1) - Fib_{n+1} + 2∑i=1n=Fibn+2×(n−1)−Fibn+1+2 Fib1=1,Fib2=1,Fibi=Fibi−1+Fibi−2Fib_1 = 1,Fib2 = 1,Fib_i = Fib_{i-1}+Fib_{i-2}Fib1=1,Fib2=1,Fibi=Fibi−1+Fibi−2
