|
|
A307455
|
|
a(n) is the number of canonical polygons with n edges having exactly 1 line of reflection symmetry.
|
|
8
|
|
|
1, 0, 2, 2, 1, 7, 6, 28, 27, 107, 94, 488, 386, 2066, 1630, 8392, 6780, 34962, 28056, 147356, 117621, 622558, 500525, 2657666, 2149374
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
3,3
|
|
COMMENTS
|
For n even, the symmetry line passes through two opposite vertices, or cuts through two opposite edges. For n odd it passes through one vertex and cuts the opposite edge. That explains the even-odd irregularity in the sequence.
|
|
LINKS
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|