I too have been getting these calls for weeks every morning around 8am. They don't leave a message and I have never tried calling back. This is on my landline. But... the name on caller ID is Wm Malone not octothorpe.
Got a call on Business line 1 from this number, ID Octothorpe (which is another name for #, btw). I answered and there was a click so I hung up. As soon as I hung up line 2 rang with this number 12130000000 with a caller ID of V09231026260000. I answered and immediately hung up.
We got a call on 9/16/2009 from 1-202-540-5120 but chose not to answer. Notice that the call was from an " Octothorpe " so we decided to check it out on the Internet. Glad we didn't answer nor will in the future.