title: find missing number from list of long
body: <p>I have <code>List&lt;long&gt; MyList</code>  which contains long numbers like <strong>7031320272 , 7031320273, 7031320277, 7031323700</strong><br />
  and a range, let's say [<strong>7031320270, 7031324000</strong>].</p>
  <p>Now i want to find all the numbers in that range that are missing from <code>MyList</code><br />
  I have already tried with <code>Enumerable.Range</code> without luck as it deals with only int values,
  <a href="https://stackoverflow.com/questions/2475795/c-sharp-check-for-missing-number-in-sequence">as given here</a></p>
  <h1>edit</h1>
  <p>I know the First and last number in the List. How to know the missing ones from the given range</p>