A211179 Number of free polypentagrams with n cells.

1, 1, 5, 31, 238, 2020, 17754, 160820, 1479536, 13792972, 129839465

Offset

1,3

Comments

A polypentagram is a plane figure made of five-pointed stars joined edge to edge. Free means that mirror images are counted as the same polypentagram.

Links

Table of n, a(n) for n=1..11.

George Sicherman, Catalogue of Polypentagrams

Example

Five different figures can be formed by joining 3 pentagrams, so a(3) = 5.

Crossrefs

Cf. A103465, A000105, A000507.

Sequence in context: A213048 A349535 A069321 * A177797 A293717 A186859

Adjacent sequences: A211176 A211177 A211178 * A211180 A211181 A211182

Keyword

nonn,hard,more

Author

George Sicherman, Feb 01 2013

Extensions

a(6)-a(11) from Aaron N. Siegel, May 23 2022

Status

approved