title: Generate a sequence of characters from 'A'-'Z'
body: <p>I can make a sequence of numbers like this:</p>
  
  <pre><code>s = seq(from=1, to=10, by=1)
  </code></pre>
  
  <p>How do I make a sequence of characters from A-Z? This doesn't work:</p>
  
  <pre><code>seq(from=1, to=10)
  </code></pre>