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A044045
Same as A038392 except for initial term.
3
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
0,3
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.
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
CROSSREFS
Cf. A121178.
Sequence in context: A150116 A150117 A038392 * A150118 A343417 A150119
KEYWORD
nonn
EXTENSIONS
More terms from Emeric Deutsch, Mar 14 2004
STATUS
approved