Proposition 8 in the summary of Bas Jansen's paper features a triangle constructed inside another triangle. The summary is in Dutch but this seems to be saying that the outer triangle has twice the area of the inner.
Having gone through the rest of the paper I can't work out what this triangle has to do with Mersenne numbers or the Lucas Lehmer test. Can someone help elaborate on the connection here please?
I've attached a clipping of the proposition.
