A044045 Same as A038392 except for initial term.

0, 1, 2, 6, 19, 71, 274, 1117, 4650, 19819, 85710, 375712, 1664203, 7439593, 33515758, 152019560, 693625265, 3181528275, 14661581030, 67850297506, 315187646601, 1469195636293, 6869889703638, 32215399021901, 151467334017864, 713881817440421, 3372142139764434

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• B. N. Cyvin, E. Brendsdal, J. Brunvoll, S. J. Cyvin, A class of polygonal systems representing polycyclic conjugated hydrocarbons: Catacondensed monoheptafusenes, Monat. f. Chemie, 125 (1994), 1327-1337.
• S. J. Cyvin, B. N. Cyvin, J. Brunvoll and E. Brendsdal, Enumeration and Classification of Certain Polygonal Systems Representing Polycyclic Conjugated Hydrocarbons: Annelated Catafusenes, Journal of Chemical Information and Modeling [formerly, J. Chem. Inform. Comput. Sci.], 34 (1994), pp. 1174-1180.
• F. Harary and R. C. Read, The enumeration of tree-like polyhexes, Proc. Edinburgh Math. Soc. (2) 17 (1970), 1-13.
• Eric W. Weisstein, Fusene, MathWorld-A Wolfram Web Resource.

Crossrefs

Cf. A121178.

Formula

G.f.: (2*(1-z)^2 - (1-z)*f(z) - f(z^2))/(4*z*(1-z)) where f(z) = sqrt(1 - 6z + 5z^2). - Emeric Deutsch, Mar 14 2004

Extensions

More terms from Emeric Deutsch, Mar 14 2004