I was wondering WTF was happening.

This was past month:

   516 + 518*n
   516  n=0  count=4454
  1034  n=1  count=318
  1552  n=2  count=129
  2070  n=3  count=56
  2588  n=4  count=35
  3106  n=5  count=14
  3624  n=6  count=6
  4142  n=7  count=4
  4660  n=8  count=6