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 A044049 Catafusenes (see reference for precise definition). 0
 0, 0, 1, 7, 31, 139, 609, 2677, 11827, 52648, 236071, 1065774, 4841428, 22115678, 101531221, 468224323, 2168076055, 10076177264, 46986612235, 219777649588, 1030892581741, 4848039893338, 22853638285655, 107970202258065 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Table of n, a(n) for n=0..23. S. J. Cyvin et al., Enumeration and Classification of Certain Polygonal Systems Representing Polycyclic Conjugated Hydrocarbons: Annelated Catafusenes, J. Chem. Inform. Comput. Sci., 34 (1994), 1174-1180. FORMULA 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 CROSSREFS Cf. A002212 (U), A055879 (V). Sequence in context: A282857 A296573 A180147 * A255284 A005825 A086901 Adjacent sequences: A044046 A044047 A044048 * A044050 A044051 A044052 KEYWORD nonn AUTHOR N. J. A. Sloane EXTENSIONS More terms from Emeric Deutsch, May 02 2004 STATUS approved

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Last modified September 30 21:54 EDT 2023. Contains 365806 sequences. (Running on oeis4.)