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Number of regions in a complete but borderless regular polygon.
1

%I #11 Mar 31 2012 10:29:18

%S 6,18,43,72,145,210,364,432,768,938,1441,1680,2483,2448,4010,4480,

%T 6154,6798,9063,9000,12901,13962,17848,19152,24100,21450,31869,33824,

%U 41383,43758,52886,52920,66638,69958,82915,86760,102009

%N Number of regions in a complete but borderless regular polygon.

%C A complete borderless polygon is one where each vertex is connected to every other vertex except for adjacent vertices. Adjacent vertices are not connected by edges. The result is a polygon interior.

%F a(n) = A007678(n) - n.

%Y Cf. A007678.

%K nonn,easy

%O 5,1

%A _Stefan Hannie_, May 25 2011

%E a(8) onward corrected by _T. D. Noe_, Jun 02 2011