title: Writing a formula to reindex a column with duplicates
body: <p>I have a column of values that has ID values listed like below where its ordered numerically, but has random high values interspersed.  They're interspersed because I have another column ordered alphabetically and I added names.</p>
  
  <p>I want it to be transformed into the one on the right.  Where it goes from 1 -> N but retains the numbering if they're the same. </p>
  
  <p>Is there an easy formula anyone can think of without using VBA.</p>
  
  <pre><code>BC1              BC1
  BC123            BC2
  BC3              BC3
  BC4       -&gt;     BC4
  BC4              BC4
  BC1441           BC5
  BC5              BC6
  BC5              BC6
  BC1231           BC7
  </code></pre>