title: pandas create a series with n elements (sequential or randbetween)
body: <p>I am trying to create a <code>pandas</code> series.</p>
  
  <p>One column of the series should contain n sequential numbers. <code>[1, 2, 3, ..., n]</code>    </p>
  
  <p>One column should contain random numbers between <code>k</code> and <code>k+100</code>.   </p>
  
  <p>One column should contain random selection between strings in a list. <code>['A', 'B', 'C', ... 'Z']</code></p>