I agree, Brochymena sp.

I did a Google image search for brochymena oregon, and found:
http://egov.oregon.gov/ODA/PLANT/docs/pdf/ippm_halyomorpha.pdf

The picture on the right is Brochymena quadripustula, Rough Stink Bug, and seems to be a pretty good match.

Here on BugGuide we don't have any photos identified beyond the genus level yet, because there are twelve Brochymena found in the U.S. and Canada and as yet there seems to be no ready reference guide on how to tell them apart; some seem pretty similar to each other.

I have a key to Pentatomidae of Ohio, and will eventually get around to examining our images. Also hope to get Dr. David Ryder over here to look at them....Brochymena sometimes fold their entennae beneath them, especially if they are in an otherwise lethargic state. This one could simply be missing them from some kind of accident.

I did notice that it was in the same spot for at least several hours, which was very helpful, since the sun moved around and made the photos much sharper.

Thanks Stephen and Stephen.
Why doesn't it seem to have any antennae?

Not sure what's going on with the antennae, whether they are somehow tucked away or what. Normally on a Brochymena the antennae emerge from the sides of the "nose," about halfway between the eye and the tip of the nose. They are relatively large and thick and stick out quite a ways.