A121211 -id:A121211 - cp's OEIS frontend

A119708 Number of free hexagonal polygons of symmetry class D_(3h) and area n.

Original entry on oeis.org

0, 0, 1, 1, 0, 1, 1, 0, 1, 4, 0, 3, 4, 0, 3, 12, 0, 6, 19, 0, 10, 41, 0, 16, 72, 0, 28, 149, 0, 50, 72, 0, 87, 557, 0

Offset: 1

N. J. A. Sloane, Aug 27 2006

Markus Voege, Anthony J. Guttmann and Iwan Jensen, "On the number of benzenoid hydrocarbons", J. Chem. Inf. Comput. Sci., (2002), vol. 42, 456-466.

Cf. A121212, A121211, A121210, A120991.

A123140 Number of benzenoids with 23 hexagons, D_(2h) symmetry and containing 2n carbon atoms.

Original entry on oeis.org

1, 3, 3, 6, 13, 19, 24, 35, 45, 79, 70, 108, 70, 169, 0, 103

Offset: 32

Parthasarathy Nambi, Oct 01 2006

			If 2n=64 then the number of benzenoids with 23 hexagons with D_(2h) symmetry is 1.
If 2n=94 then the number of benzenoids with 23 hexagons with D_(2h) symmetry is 103.

G. Brinkmann, G. Caporossi and P. Hansen, A Survey and New Results on Computer Enumeration of Polyhex and Fusene Hydrocarbons, J. Chem. Inf. Comput. Sci., vol. 43 (2003) 842-851. See Table 6 column 5 on page 847.

Cf. A121211, A122539, A121964, A122736, A123044, A123106, A123105, A123104.

Sum_n a(n) = 748 = A121211(23). - Andrey Zabolotskiy, Nov 09 2023

Name and offset corrected and a(46) = 0 inserted by Andrey Zabolotskiy, Nov 09 2023

cp's OEIS Frontend

A119708 Number of free hexagonal polygons of symmetry class D_(3h) and area n.

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A123140 Number of benzenoids with 23 hexagons, D_(2h) symmetry and containing 2n carbon atoms.

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