In the following matrix
\documentclass[10pt]{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
\begin{bmatrix}
a_{11} & a_{12} & a_{13} & a_{14} & a_{15} & a_{16} & 0 & \cdots & 0 & & & & \\
a_{21} & a_{22} & a_{23} & a_{24} & a_{25} & a_{26} & 0 & \cdots & 0 & & & & \\
a_{31} & a_{32} & a_{33} & a_{34} & a_{35} & a_{36} & 0 & \cdots & 0 & & & & \\
a_{41} & a_{42} & a_{43} & a_{44} & a_{45} & a_{46} & 0 & \cdots & 0 & & & & \\
0 & 0 & 0 & 1/24 & -9/8 & 9/8 & -1/24 & 0 & \cdots & & & & \\
\vdots & \vdots & \vdots & 0 & 1/24 & -9/8 & 9/8 & -1/24 & 0 & \cdots & & & \\
& & & \vdots & 0 & 1/24 & -9/8 & 9/8 & -1/24 & 0 & \cdots & & \\
& & & & \vdots & 0 & 1/24 & -9/8 & 9/8 & -1/24 & 0 & \cdots & \\
& & & & & \vdots & 0 & \ddots & 0 & & & &
\end{bmatrix}
\end{align}
\end{document}
I'm receiving the message
! Extra alignment tab has been changed to \cr.
<recently read> \endtemplate
l.17 \end{align}
Cannot understand why, I have checked all & and they all match, tried to add $0$ in empty cells, but same error.
