Tucker is 18 1/2 weeks old. I'm at work during the day so he sleeps from 8-12, then is up for an hour and sleeps from 1-5 when I get home. He's then up from 5 til around 10 but he will usually nap for a short time somewhere in there - maybe 30 minutes around 7ish. He'll then sleep from 10pm-6:15am. When I get home for lunch at 12 he's usually in such a deep sleep it takes him a minute or so to wake up and get out of his crate. At 5, however, it only takes him a couple seconds to stretch and be ready to play
The same is true for 6:15 AM. He's bouncing off the walls as soon as I let him out.