Two or more spots are placed anywhere on a circle's circumference. Every pair is joined by a straight line. Given n spots, what is the maximum number of regions into which the circle can be divided?

(In reply to researched by Charlie)

Nice work Charlie.

I did the research only to 5 points and never saw the 31.  So I stcked to the regular polygon which was clearly wrong.
The corrected formula is n +Sloane's A006522 http://www.research.att.com/projects/OEIS?Anum=A006522

Charlie, the SHIFT-ENTER as opposed to <br>, works fine, thanks

Posted by Hugo on 2004-12-28 10:09:24