The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A341762 The number of vertices 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. 4
 2, 5, 19, 65, 195, 461, 971, 1737, 2995, 4617, 7203, 10385, 14779, 20125, 27155, 35481, 46051, 58277, 73395, 90323, 111403, 134765, 162539, 193385, 229515, 269301, 315331, 365617, 423195, 485617, 556603, 633145, 719299, 811845, 915275, 1025921, 1148811, 1279757, 1424395, 1577723, 1746803 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A341688 for a description of the ellipse. Curiously the only ellipses found that have vertices with three or more lines crossing that are not on the x or y axes are those with a number of vertices equal to a multiple of ten. The terms are from numeric computation - no formula for a(n) is currently known. LINKS Scott R. Shannon, Image of the vertices for n = 3. Scott R. Shannon, Image of the vertices for n = 5. Notice the off-axis vertices that have three lines crossing. Scott R. Shannon, Image of the vertices for n = 9. Scott R. Shannon, Image of the vertices for n = 10. Notice the off-axis vertices that have three or four lines crossing. Scott R. Shannon, Image of the vertices for n = 20. Notice the off-axis vertices that have three or more lines crossing. Scott R. Shannon, Image of the vertices for n = 21. Wikipedia, Ellipse. CROSSREFS Cf. A341688 (regions), A341764 (edges), A341800 (n-gons), A007678, A092867, A255011, A331929, A331931, A333075. Sequence in context: A047116 A148433 A148434 * A341878 A062122 A148435 Adjacent sequences:  A341758 A341759 A341761 * A341763 A341764 A341765 KEYWORD nonn AUTHOR Scott R. Shannon and N. J. A. Sloane, Feb 19 2021 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 8 19:28 EDT 2021. Contains 343666 sequences. (Running on oeis4.)