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A211179 Number of free polypentagrams with n cells. 2
1, 1, 5, 31, 238, 2020, 17754, 160820, 1479536, 13792972, 129839465 (list; graph; refs; listen; history; text; internal format)
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
George Sicherman, Catalogue of Polypentagrams
EXAMPLE
Five different figures can be formed by joining 3 pentagrams, so a(3) = 5.
CROSSREFS
Sequence in context: A213048 A349535 A069321 * A177797 A293717 A186859
KEYWORD
nonn,hard,more
AUTHOR
George Sicherman, Feb 01 2013
EXTENSIONS
a(6)-a(11) from Aaron N. Siegel, May 23 2022
STATUS
approved

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Last modified April 19 17:39 EDT 2024. Contains 371797 sequences. (Running on oeis4.)