Same here. Got 6 of these missed calls from both numbers and a receptionist said that I had reached a company called "Talks" or "Toxx". She hastily hung up the phone and I didn't get any other info. The 4013 number just rang as a fax.

My direct dial work number has received calls from this number and from 314-683-4013.  It seems to be an automatic dialer from a fax machine with beeps instead of voice when I answer.
I called the number and it was immediately answered by an operator who thanked me for calling and reporting the annoyance.