A341764 - OEIS

%I #8 Feb 20 2021 13:34:51

%S 1,8,42,148,426,984,2022,3604,6138,9492,14642,21108,29902,40728,54786,

%T 71604,92722,117384,147578,181810,223782,270808,326262,388308,460446,

%U 540424,632322,733364,848318,973732,1115422,1269108,1441122,1626888,1833406,2055444,2300822,2563544,2852358,3160050,3497562

%N The number of edges on a 2 by 1 ellipse formed by the straight line segments mutually connecting all points formed by dividing the ellipse into 2n equal angle sectors from its origin.

%C The terms are from numeric computation - no formula for a(n) is currently known.

%C See A341688 for a description of the ellipse and images of the regions, and A341762 for images of the vertices.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Ellipse">Ellipse</a>.

%F a(n) = A341688(n) + A341762(n) - 1.

%Y Cf. A341688 (regions), A341762 (vertices), A341800 (n-gons), A007678, A092867, A255011, A331929, A331931, A333075.

%K nonn

%O 1,2

%A _Scott R. Shannon_ and _N. J. A. Sloane_, Feb 19 2021