This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A258017 #17 Feb 16 2025 08:33:25 %S A258017 0,0,1,0,1,1,3,3,16,23,80,183,564 %N A258017 Number of one-sided fusenes (not necessarily planar) of perimeter 2n, counted up to rotations. %C A258017 This sequence counts fusenes up to rotations, but with no turning over allowed. Fusenes are like polyhexes with additional criteria that no holes are allowed, while on the other hand, helicene-like self-touching or self-overlapping configurations are included in the count here. Cf. the links and further comments at A258019. %C A258017 For n >= 1, a(n) gives the total number of terms k in A258013 with binary width = 2n + 1, or equally, with A000523(k) = 2n. %H A258017 Xiaofeng Guo, Pierre Hansen, and Maolin Zheng, <a href="http://dx.doi.org/10.1016/S0166-218X(01)00180-9">Boundary uniqueness of fusenes</a>, Discrete Applied Mathematics 118 (2002), pp. 209-222. %H A258017 Pornrat Ruengrot and Duangkamon Baowan, <a href="https://doi.org/10.1016/j.commatsci.2023.112181">Classification of k-defect holes on a graphene sheet</a>, Comp. Materials Sci. (2023) Vol. 225, 112181. %H A258017 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Fusene.html">Fusene</a> %H A258017 Wikipedia, <a href="http://en.wikipedia.org/wiki/Helicene">Helicene</a> %F A258017 Other identities and observations. For all n >= 1: %F A258017 a(n) = 2*A258019(n) - A258018(n). %F A258017 a(n) >= A258204(n). %Y A258017 Cf. A258018, A258019, A258204. %Y A258017 Cf. A258013. %K A258017 nonn,more %O A258017 1,7 %A A258017 _Antti Karttunen_, Jun 02 2015