It's kind of hard to see what's what from your picture, but the only thing I can find remotely similar looking are the double bar increase and the double make-one increase. The only difference is that neither of these increases have a double row of stitches down the middle as yours does. But perhaps that's just two stitches between the increases instead of just one???
I dunno--maybe look those two increases up and see if either is what you want.