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 A038141 #17 Jul 08 2025 22:07:49 %S A038141 0,0,0,0,0,0,0,0,0,0,0,0,1,11,149,1618,15123,125764 %N A038141 Number of planar polyhexes with n cells with at least two holes, all holes having size at least two. %C A038141 Planar, proper multiple coronoid systems enumerated by area. Free systems are enumerated, i.e., translations, rotations and reflections are regarded as the same configuration. %C A038141 The last term includes 4 polyhexes with three holes. %D A038141 S. J. Cyvin, J. Brunvoll, R. S. Chen, B. N. Cyvin, F. J. Zhang, Theory of Coronoid Hydrocarbons II, Lecture Notes in Chemistry 62, Springer-Verlag, 1994. (see table 3.2, p. 66) %H A038141 J. V. Knop et al., <a href="https://doi.org/10.1021/ci00066a010">Use of small computers for large computations: enumeration of polyhex hydrocarbons</a>, J. Chem. Inf. Comput. Sci., 30 (1990), 159-160. %Y A038141 Cf. A018190. %Y A038141 Cf. A000228 (hexagonal free polyominoes), A038140 (planar single coronoids). %K A038141 nonn,more %O A038141 1,14 %A A038141 _N. J. A. Sloane_ %E A038141 Edited by Markus Voege (markus.voege(AT)inria.fr), Dec 03 2003