User blog comment:Argorrath/Treyarch posts a message of zombies; possibly hinting to a DLC 4/@comment-173.55.118.141-20130802214339

There are 13 days between Sept. 22 and Oct. 6.

There are 43 days between Oct. 6 and Nov. 19.

And there are 20 days between Nov. 19 and Dec. 10.

13,43,20. Could this mean anything?