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 A121181 #15 Jul 29 2023 14:34:57 %S A121181 0,0,1,2,13,19,87,128,529,739,3012 %N A121181 Alkane systems (see Cyvin reference for precise definition). %H A121181 S. J. Cyvin, B. N. Cyvin, J. Brunvoll, and J. Wang, <a href="https://doi.org/10.1016/S0022-2860(97)00419-5">Enumeration of staggered conformers of alkanes and monocyclic cycloalkanes</a>, J. Molec. Struct., 445 (1998), 127-137. See Table 3, branched, column C_2. %H A121181 S. J. Cyvin, Jianji Wang, J. Brunvoll, Shiming Cao, Ying Li, B. N. Cyvin, and Yugang Wang, <a href="https://doi.org/10.1016/S0022-2860(97)00025-2">Staggered conformers of alkanes: complete solution of the enumeration problem</a>, J. Molec. Struct. 413-414 (1997), 227-239. See Table 6, branched, column C_2. %Y A121181 Cf. columns of Table 6 from Cyvin et al. (1997) and Table 3 of Cyvin et al. (1998), in pairs (branched, unbranched): this sequence and A121189 (C_2), A121182 and A121190 (C_s), A121183 and A121184 (C_1), A121191 and A121192 (C_i), A121185 and A121186 (spectral isomers), A121187 and A121188 (stereoisomers). %Y A121181 Cf. A121180. %K A121181 nonn,more %O A121181 4,4 %A A121181 _N. J. A. Sloane_, Aug 17 2006