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
KEYWORD
nonn
AUTHOR
Scott R. Shannon and N. J. A. Sloane, Feb 19 2021
STATUS
approved