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A231091 Number of distinct (modulo reflection and rotation) unicursal star polygons (not necessarily regular, no edge joins adjacent vertices) that can be formed by connecting the vertices of a regular n-gon. 2
0, 0, 0, 0, 1, 1, 5, 27, 175, 1533, 14361, 151575, 1735869, 21594863 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

COMMENTS

For polygons in general see A000939 and A000949, and especially the Golomb-Welch reference. - N. J. A. Sloane, Nov 21 2013

LINKS

Table of n, a(n) for n=1..14.

Stewart Gordon, The five possible stars for n=7 (SVG file)

Wikipedia, Unicursal hexagram

EXAMPLE

For n=5, only solution is the regular pentagram.

For n=6, only solution is the unicursal hexagram (see Wikipedia link).

For n=7, two regular heptagrams and three irregular forms are possible.

CROSSREFS

Cf. A000939, A000940.

Sequence in context: A091101 A185622 A225309 * A205774 A326094 A232683

Adjacent sequences:  A231088 A231089 A231090 * A231092 A231093 A231094

KEYWORD

nonn,nice

AUTHOR

Stewart Gordon, Nov 03 2013

STATUS

approved

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Last modified December 3 18:22 EST 2020. Contains 338910 sequences. (Running on oeis4.)