I knew the second one sounded familiar! They use it on the euler's identity proof video.This music piece (and others by Wim Mertens) is excellent. It's especially good if you're doing mind-numbing calculations like derivatives. With a little practice, you can do it on the rythm of the music.
And this nice piece of music makes you feel like a genius and makes you see all the structures, numbers and theorems flying all around you: Check out other music from that soundtrack!