Match Strings, not preceded by a-z or A-Z, and which contains 1324
<p>Using regex, I want to match strings in a text if:</p>

<ol>
<li>They contain <code>1324</code> as a substring</li>
<li>The <code>1324</code> substring is not preceded by one or more characters like <code>a-zA-Z</code></li>
</ol>

<p>For instance:</p>

<ul>
<li>'<code>1324test</code>' should be matched</li>
<li>'<code>1324</code>' should be matched</li>
<li>'<code>test test :/1324test</code>' should be matched</li>
<li>'<code>test test 1324test</code>' should be matched</li>
<li>'<code>test test 1324</code>' should be matched</li>
<li>'<code>test test test1324test</code>' should <strong>NOT</strong> be matched</li>
</ul>

<p>Here's my attempt: <code>[^a-zA-Z]+1324</code></p>

<p>How can I do this ?</p>