# What does fibonnaci of 2 on n mean?

http://en.wikipedia.org/wiki/Cassini%27s_identity

In this equation:

$F_{n-1}F_{n+1}-F^2_n=(-1)^n$

$F^2_n$, what does that mean? Is it a summation signs for n to 2? I don't know what it means.

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It's the number $F_n$ to the power of $2$. – EuYu Nov 18 '12 at 1:29
ah ok thanks you could have answered instead – George Nov 18 '12 at 1:30

$F_n^2$ is the square of the $n^{\text{th}}$ Fibonacci number.