An \( n \times n \) matrix is formed using \( 0, 1 \) and \( -1 \) as its elements. The number of such matrices which are skew symmetric is:
Show Hint
For skew symmetric matrices:
\begin{itemize}
\item Diagonal elements are always zero.
\item Only upper triangular entries are independent.
\item Number of independent entries = \( \frac{n(n-1)}{2} \).
\end{itemize}