F(-n)=(-1)^(n+1)F(n)
From specialfunctionswiki
Theorem
The following formula holds: $$F(-n)=(-1)^{n+1}F(n),$$ where $F(n)$ denotes the $n$th Fibonacci number.
The following formula holds: $$F(-n)=(-1)^{n+1}F(n),$$ where $F(n)$ denotes the $n$th Fibonacci number.
