How to remove values from a list that are less than a target value from the previous number
<p>Given a sorted list of increasing numbers, I'm trying to create a new list that only keeps values that are at least 3 greater than the previous number.  I have tried some conditional statements, but fail to get the correct format. For example, from </p>

<pre><code>a = [3,4,8,12,14,16]
</code></pre>

<p>we would obtain</p>

<pre><code>new_a = [3,8,12,16]
</code></pre>

<p>Only 14 would drop out because it is less than 3 away from 12, but keep 16 because it is greater than 3 from 12. Also 4 would drop out. Any help would be appreciated!</p>