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A211179 Number of free polypentagrams with n cells. 2

%I #24 Apr 26 2023 07:09:33

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

%N Number of free polypentagrams with n cells.

%C 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.

%H George Sicherman, <a href="https://sicherman.net/polypgrams/index.html">Catalogue of Polypentagrams</a>

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

%Y Cf. A103465, A000105, A000507.

%K nonn,hard,more

%O 1,3

%A _George Sicherman_, Feb 01 2013

%E a(6)-a(11) from _Aaron N. Siegel_, May 23 2022

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Last modified March 28 17:42 EDT 2024. Contains 371254 sequences. (Running on oeis4.)