Sounds like some1 is trying to find a house to break in to...maybe they're trying to make sure the people living at the house don't have high IQs so that they wouldn't know how to defend themselves/what actions to take to get robbers caught. Once you have some1's home phone#, finding out their address is not too difficult.
I get calls from this number frequently, at least once a day. I never pick up. They always seem to hang up after 4 rings, just before the machine picks up, suggesting to me that they only want to speak to you live.