\documentclass[a4paper]{article}
\usepackage{amsmath}
\usepackage{rotating}
\usepackage{xepersian}
\begin{document}
\begin{align*}
I = \begin{bmatrix}
1536 & 2712 & 768 & 24 \\
\dfrac{27577}{27} + \dfrac{2345}{9}r & \dfrac{46793}{18} + \dfrac{5761}{6}r & \dfrac{11644}{9} - \dfrac{2044}{3}r & \dfrac{6709}{54} - \dfrac{9331}{18}r & 1-21r \\
\dfrac{3200}{27}  - \dfrac{4256}{9}r & \dfrac{10733}{9} - \dfrac{1043}{3}r & \dfrac{21752}{9} + \dfrac{4984}{3}r & \dfrac{3218}{27} - \dfrac{2842}{9}r & 120-504r & 1-21r \\
1-21r & 120-504r & 1191-315r & 2416+1680r & 1191-315r & 120-504r & 1-21r \\
\ddots & \ddots & \ddots & \ddots & \ddots & \ddots & \ddots \\
& 1-21r & 120-504r & 1191-315r & 2416+1680r & 1191-315r & 120-504r & 1-21r \\
& & 1-21r & 120-504r & \dfrac{32158}{27} - \dfrac{2842}{9}r & \dfrac{21752}{9} + \dfrac{4984}{3}r & \dfrac{10733}{9} - \dfrac{1043}{3}r & \dfrac{3200}{27} - \dfrac{4256}{9}r \\
& & & 1-21r & \dfrac{6709}{54} - \dfrac{9331}{18}r & \dfrac{11644}{9} - \dfrac{20444}{3}r & \dfrac{46793}{18}+\dfrac{5761}{6}r & \dfrac{27577}{27}+ \dfrac{2345}{9}r \\
& & & & 24 & 768 & 2712 & 1536
\end{bmatrix}
\end{align*}
\end{document}