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 A026298 #18 Jul 08 2025 17:50:48 %S A026298 4,28,176,950,4908,24402,119240,575348,2757460,13157752,62638788, %T A026298 297832008,1415550920,6728600060,31998023632,152271569872, %U A026298 725231959452,3457304575812,16497751608120,78804354881238,376806016649964,1803539487096138,8641075826669256,41441524062045660 %N A026298 Number of polyhexes of class PF2. %C A026298 See reference for precise definition. %C A026298 Cyvin et al. has incorrect a(13) = 119204 and a(14) = 575312 due to using incorrect value for A039919(5); cf. A039659. - _Sean A. Irvine_, Sep 24 2019 %H A026298 S. J. Cyvin, Zhang Fuji, B. N. Cyvin, Guo Xiaofeng, and J. Brunvoll, <a href="https://doi.org/10.1021/ci00009a021">Enumeration and classification of benzenoid systems. 32. Normal perifusenes with two internal vertices</a>, J. Chem. Inform. Comput. Sci., 32 (1992), 532-540. %F A026298 a(n + 4) = 3 * (N(n+2) - 6*N(n+1) + 8*N(n)) + A039919(floor((n+1)/2)) where N(n) = A002212(n) [from Cyvin]. - _Sean A. Irvine_, Sep 24 2019 %Y A026298 Cf. A026106, A026118, A030519, A030520, A030525, A030529, A030532, A030534, A002212, A039919. %K A026298 nonn %O A026298 7,1 %A A026298 _N. J. A. Sloane_ %E A026298 Corrected and extended by _Sean A. Irvine_, Sep 24 2019