Consider the following screenshot. I want to vertically align the left `=` as shown in the *expected* part.

```
\documentclass[border=12pt,preview]{standalone}
\usepackage{amsmath}
\begin{document}
\abovedisplayskip=0pt\relax
\begin{align*}
    a_1=4   &= 4 + 3 \times 0 \\
    a_2=7   &= 4 + 3 \times 1 \\
    a_3=10  &= 4 + 3 \times 2 \\
    a_4=13  &= 4 + 3 \times 3 \\
    a_5=16  &= 4 + 3 \times 4 \\
    a_6=19  &= 4 + 3 \times 5 \\
    a_7=22  &= 4 + 3 \times 6 
\end{align*}
\end{document}

```

[![enter image description here](https://i.stack.imgur.com/eMPmh.png)](https://i.stack.imgur.com/eMPmh.png)