title: Repeating replacement pattern number of times in vim
body: <p>I want to do the following in vim.</p>
  
  <ul>
  <li>Replace <code>a,2</code> with <code>a@,a@</code></li>
  <li>Replace <code>b,3</code> with <code>b@,b@,b@</code></li>
  <li>Replace <code>c,6</code> with <code>c@,c@,c@,c@,c@,c@</code>
  and so on</li>
  </ul>