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A045908 Number of catafusenes with C_{2v}(b) symmetry (see reference for precise definition). 3
0, 1, 3, 13, 49, 203, 833, 3533, 15133, 65891, 289865, 1288491, 5774847, 26076165, 118501583, 541605705, 2487893725, 11480052755, 53188676889, 247337349095, 1154007818323, 5400694067345, 25345508567027, 119251934995963, 562414480094339, 2658260322324013 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Column C_{2v}(b) in Table 6 and Eq. (53) in Cyvin. - Sean A. Irvine, Mar 26 2021

LINKS

Table of n, a(n) for n=0..25.

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

FORMULA

a(n) = (1/2) * (b(n+1) - b(n) - b(n/2)) where b(n)=A002212(n) is understood to be 0 for noninteger arguments. - Sean A. Irvine, Mar 26 2021

CROSSREFS

Cf. A002212.

Sequence in context: A178934 A218420 A241775 * A118589 A113237 A284329

Adjacent sequences:  A045905 A045906 A045907 * A045909 A045910 A045911

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Sean A. Irvine, Mar 26 2021

STATUS

approved

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Last modified December 2 08:31 EST 2021. Contains 349437 sequences. (Running on oeis4.)