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 A044049 #16 Jun 26 2022 23:21:44 %S A044049 0,0,1,7,31,139,609,2677,11827,52648,236071,1065774,4841428,22115678, %T A044049 101531221,468224323,2168076055,10076177264,46986612235,219777649588, %U A044049 1030892581741,4848039893338,22853638285655,107970202258065 %N A044049 Catafusenes (see reference for precise definition). %H A044049 S. J. Cyvin et al., <a href="https://doi.org/10.1021/ci00021a026">Enumeration and Classification of Certain Polygonal Systems Representing Polycyclic Conjugated Hydrocarbons: Annelated Catafusenes</a>, J. Chem. Inform. Comput. Sci., 34 (1994), 1174-1180. %F A044049 G.f.: (U(z) + V(z) + U(z)^2 + U(z^2) - U(z^2)*V(z) + V(z^3))/2 + (U(z)^3 - U(z^3))/6 - V(z)/z + 1, where U(z) = (1 - 3*z - sqrt(1-6*z+5*z^2)) / (2*z) and V(z) = (1 - z^2 - sqrt(1-6*z^2+5*z^4)) / (2*z*(1-z)) (from eq. (26)-(29) of the Cyvin et al. paper). - _Emeric Deutsch_, May 02 2004 %Y A044049 Cf. A002212 (U), A055879 (V). %K A044049 nonn %O A044049 0,4 %A A044049 _N. J. A. Sloane_ %E A044049 More terms from _Emeric Deutsch_, May 02 2004