A341764 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.

1, 8, 42, 148, 426, 984, 2022, 3604, 6138, 9492, 14642, 21108, 29902, 40728, 54786, 71604, 92722, 117384, 147578, 181810, 223782, 270808, 326262, 388308, 460446, 540424, 632322, 733364, 848318, 973732, 1115422, 1269108, 1441122, 1626888, 1833406, 2055444, 2300822, 2563544, 2852358, 3160050, 3497562

Offset: 1

Author

Scott R. Shannon and N. J. A. Sloane, Feb 19 2021

Keywords

• nonn

Comments

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

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

Links

• Wikipedia, Ellipse.

Crossrefs

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

Formula

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