PS and what about the numbers of vertices (including both boundary points and interior intersection points)? On Thu, Feb 7, 2019 at 1:09 PM Neil Sloane <njasloane at gmail.com> wrote: > No of regions in a strip of rectangles: A306302 > > Given enough terms, will probably be guessable > 4, 16, 46, 104, 214 is not enough > > >