A045908 Number of catafusenes with C_{2v}(b) symmetry (see reference for precise definition).

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

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