<math>
<merror>
<apply>
<equivalent/>
<ci>n</ci>
<apply>
<divide/>
<mx:a-factorial><ci>n</ci></mx:a-factorial>
<mx:a-factorial>
<apply><minus/><ci>n</ci><cn>1</cn></apply>
</mx:a-factorial>
</apply>
</apply>
</merror>
</math>