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%I #27 Apr 26 2023 07:09:29
%S 1,1,2,7,25,118,551,2812,14445,76092,403976,2167116,11698961,63544050,
%T 346821209,1901232614
%N Number of polyominoes that can be formed from n regular unit pentagons (or polypents of order n).
%C Number of 5-polyominoes with n pentagons. A k-polyomino is a non-overlapping union of n regular unit k-gons.
%C Unlike A051738, these are not anchored polypents but simple polypents. - _George Sicherman_, Mar 06 2006
%C Polypents (or 5-polyominoes in Koch and Kurz's terminology) can have holes and this enumeration includes polypents with holes. - _George Sicherman_, Dec 06 2007
%H Erich Friedman, <a href="https://erich-friedman.github.io/mathmagic/">Math Magic</a>, September and November 2004.
%H Matthias Koch and Sascha Kurz, <a href="http://arxiv.org/abs/math/0605144">Enumeration of generalized polyominoes</a> (preprint) arXiv:math.CO/0605144
%H Sascha Kurz, <a href="http://www.mathe2.uni-bayreuth.de/sascha/oeis/k-polyominoes.html">k-polyominoes</a>.
%H George Sicherman, <a href="https://sicherman.net/polypents/index.html">Catalogue of Polypents</a>, at Polyform Curiosities.
%e a(3)=2 because there are 2 geometrically distinct ways to join 3 regular pentagons edge to edge.
%Y Cf. A103465, A103466, A103467, A103468, A103469, A103470, A103471, A103472, A103473, A120102, A120103, A120104.
%Y Cf. A000105, A000577, A000228.
%K more,nonn
%O 1,3
%A _Sascha Kurz_, Feb 07 2005; definition revised and sequence extended Apr 12 2006 and again Jun 09 2006
%E Entry revised by _N. J. A. Sloane_, Jun 18 2006
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