title: Formula for data that looks like a hockey stick
body: <p>The following are X and Y values:</p>
  
  <pre><code>X    Y
  20   10
  100  25
  140  50
  </code></pre>
  
  <p>It would be nice if I could approximately represent this data as a formula and plug in any arbitrary value of X from 20 to 140. The data seems to be kind of like a hockey stick curve. Or is it more exponential? I could code this to just create linear segments between those three points but it would be way better if a formula could give me more of a smooth result. The numbers above aren't fixed in stone. They can vary a little. As long as the formula gets me in the ballpark.</p>