title: Algorithm to find sequence in longer number
body: <p>this is a tough one.<br>
  I haven't been able to work it out for quite some time now, so now I am hoping some of you might know an answer.
  I have a long number a bit like this one here:</p>
  
  <p><strong>122111312121142113121</strong>  </p>
  
  <p>There are no numbers higher than four or lower than one.<br>
  Now I need to find out if a random sequence (random numbers, but nothing other than 1-4, and random length) exists within that longer number.<br>
  As an example I have the sequence <strong>13121211</strong> and I need to find out if it is in the above array (In this case it is, but there's always a chance it isn't!).
  Unfortunately I am limited to only using pure HTML and JavaScript, no jQuery or any Frameworks like AngularJS.
  The number has about 600 characters, so a solution without having to type all those into an array would be awesome!<br>
  I feel like there should be an easy way to solve this, but I just can't figure out how.  </p>
  
  <p>Thanks in advance !  :)</p>