title: functions that f(n) is not O(g(n)) and g(n) is not O(f(n))
body: <p>Are there any functions such as f(n) and g(n) that both;</p>
  
  <pre><code>f(n) != O(g(n)) and
  g(n) != O(f(n)). 
  </code></pre>
  
  <p>Are there any functions that fulfills the requirements at the above?</p>