title: Convert an integer to an alphanumeric string with as few characters as possible
body: <p>I am looking for a way to reduce a decimal integer representation to a string with the fewest characters possible.</p>
  <p>E.g. hexadecimal uses the letters A-F on top of the decimal numbers.</p>
  <pre><code>hex(123)
  </code></pre>
  <p>Is there a smooth way to make use of all letters to reduce the string length even more?</p>