A120386 Number of isomers of polyhex hydrocarbons with C_(2h) symmetry with nineteen hexagons.

0, 3, 17, 66, 189, 589, 1677, 3829, 7948, 15649, 25543, 26931, 15472

Offset: 54

Author

Parthasarathy Nambi, Aug 27 2006

Keywords

• nonn

Comments

See Table 4 column 3 on page 615 of the paper by Caporossi and Hansen. Also the sequence starts for the hydrocarbon C_54H_18. If the number of carbons is an odd number then the number of isomers with this symmetry is zero.

Examples

			If the number of carbons is 56 then the number of isomers of polyhex hydrocarbons with C_(2h) symmetry with nineteen hexagons is 3 which is the third term in the sequence.
		

References

• G. Caporossi and P. Hansen, "Enumeration of Polyhex Hydrocarbons to h=21", J. Chem. Inf. Comput. Sci., vol. 38 (1998) pp. 610-619.

Crossrefs

Cf. A018190.