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 A129021 #13 Nov 18 2019 02:06:33 %S A129021 1,1,2,4,12,19,46,70,162,239,504,726,1471,2062 %N A129021 A129017 with the third term from each triple omitted. %D A129021 J. R. Dias, The Periodic Table Set as a Unifying Concept in Going from Benzenoid Hydrocarbons to Fullerene Carbons, in "The Periodic Table: Into the 21st Century", Edited by D. H. Rouvray and R. B. King, Research Studies Press Ltd, Baldock, Hertfordshire, England, 2004, 371-396. %H A129021 Jerry Ray Dias, <a href="https://doi.org/10.1007/BF01126675">Constant-isomer benzenoid series and their polyradical subsets</a>, Theoretica Chimica Acta 81(3) (1991), 125-138; see Table 2 on p. 129. %H A129021 Jerry Ray Dias, <a href="https://doi.org/10.1021/ci00011a017">Notes on constant-isomer series</a>, J. Chem. Inf. Comput. Sci. 33 (1993), pp. 117-127; see p. 123. %H A129021 Jerry Ray Dias, <a href="https://doi.org/10.1016/0166-218X(95)00012-G">Graph theoretical invariants and elementary subgraphs of polyhex and polypent/polyhex systems of chemical relevance</a>, Discr. App. Math. 67 (1-3) (1996), pp. 79-114; see p. 98. %Y A129021 Cf. A129012-A129021. %K A129021 nonn,more %O A129021 0,3 %A A129021 _N. J. A. Sloane_, based on email from Jerry R. Dias (DiasJ(AT)umkc.edu), May 08 2007 %E A129021 Name edited by _Petros Hadjicostas_, Nov 17 2019