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%I #16 Jun 26 2022 23:21:44
%S 0,0,1,7,31,139,609,2677,11827,52648,236071,1065774,4841428,22115678,
%T 101531221,468224323,2168076055,10076177264,46986612235,219777649588,
%U 1030892581741,4848039893338,22853638285655,107970202258065
%N Catafusenes (see reference for precise definition).
%H 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 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 Cf. A002212 (U), A055879 (V).
%K nonn
%O 0,4
%A _N. J. A. Sloane_
%E More terms from _Emeric Deutsch_, May 02 2004
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