کد زیر رو قرار بدید
کد: [انتخاب]
$$PB = \left\{ {\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
0&1& \cdots &n
\end{array}}\\
{\begin{array}{*{20}{c}}
0&1& \cdots &n
\end{array}}\\
{\begin{array}{*{20}{c}}
\vdots & \vdots & \ddots & \vdots
\end{array}}\\
{\begin{array}{*{20}{c}}
0&1& \cdots &n
\end{array}}
\end{array}} \right\}$$