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.
Just got a call and I didn't answer because I was at the end of my movie. The answer machine got it but the caller didn't leave a message. So then I had to go see who called because curiosity was getting to me. It was from 202-540-5120. So I dialed the number back and I got nothing. It didn't even ring. Hum...Anyhow I decided to look the number up and I came across this site and ALL the complaints. I'm glad I didn't answer & I'll be on the look out for the number again and if I do answer it'll be with caution.