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%I #17 Dec 23 2024 14:53:46
%S 1,1,2,5,13,47
%N Number of deltahedra with 2*n faces.
%C The terms shown were found by Professor Keh-Ming Lu, Dept. of CSIE, Asia University, Taiwan. Two potentially relevant links are https://geometry.pre-college.narkive.com/JIBdcdER/concave-deltahedra-with-less-than-12-faces and https://www.kehminglu.com/books/.
%C [It would be nice if someone could look at these URLs and provide proper links. The sequence seems important enough to justify this less-than-perfect preliminary entry.]
%H Antreas Hatzipolakis, <a href="https://web.archive.org/web/*/http://list.seqfan.eu/pipermail/seqfan/2023-January/074268.html">Number of Deltahedra</a>, SeqFan Mailing List, Jan 29 2023.
%H Mathematics Stack Exchange, <a href="https://math.stackexchange.com/questions/3537381/counting-deltahedra-with-2n-faces">Counting deltahedra with 2n faces</a>.
%H Allan Turton, <a href="https://geometry.pre-college.narkive.com/JIBdcdER/concave-deltahedra-with-less-than-12-faces">Concave deltahedra with less than 12 faces</a>, NK, geometry.pre-college, 2006.
%K nonn,more,changed
%O 2,3
%A _N. J. A. Sloane_, Feb 27 2023