title: counting instances of a number but only when following another that has been repeated ex. 0,0,0,0,1
body: <p>I'm trying to count a number in excel but only when it is proceeded by another that has been repeated 4 times.  The numbers are only 0 and 1 for example <strong>0,0,0,0,1</strong>.  Because 1 was preceeded by 0 4 times the <em>count</em> would be 1.
  I have found numerous references to countif and countifs but none of those would be looking at or checking the <strong>frequency of 0</strong> to determine whether or not to count.</p>