# What does $F^2_n$ mean?

In this Wikipedia entry on Cassini's identity, I saw 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.