%I #13 May 03 2020 06:05:27
%S 4,8,16,34,63,113,185,253,438,638,854,1228,1641,1825,2783,3543,4304,
%T 5508,6748,7745,9859,11773,13653,16409,19178,21838,25770,29648,32696,
%U 38683,43899,48903,55916,62784,69604,78378,87175,95699,106993,118093,128431,142838
%N The number of vertices formed by straight line segments mutually connecting all vertices of a semicircular polygon defined in A333642.
%C See A333642 for a precise definition of the polygon and images.
%H Lars Blomberg, <a href="/A330913/b330913.txt">Table of n, a(n) for n = 1..100</a>
%Y Cf. A333642 (regions), A330911 (edges), A330914 (n-gons), A331453, A333026, A006561.
%K nonn
%O 1,1
%A _Scott R. Shannon_ and _N. J. A. Sloane_, May 02 2020
%E a(21) and beyond from _Lars Blomberg_, May 03 2020