I proudly wrote up & posted it here http://rangevoting.org/WilsonOrder.html then made mistake of telling hyperplane-arrangements expert Richard P. Stanley about it. He soon found I.J. Good & T.N. Tideman: Stirling Numbers and a Geometric Structure from Voting Theory, J. Combin. Theory, Ser. A 23,1 (1977) 34-45 http://ac.els-cdn.com/0097316577900772/1-s2.0-0097316577900772-main.pdf?_tid...' which solved my R(N,D) problem. They give a closed form in terms of sum over Stirling numbers, which I did not know. On other hand I actually think I prefer my answer to their (presumably equivalent) one, and I'm not sure their proof really is rigorous, there are a couple fine points they blissfully ignored. But basically, they scooped me 37 years ago. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)