

A122539


Number of benzenoids with 21 hexagons with D_(2h) symmetry and 60+2n carbons.


31



1, 3, 5, 8, 12, 16, 16, 42, 31, 43, 45, 73, 30, 40
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

60,2


COMMENTS

The total number of carbons in 21 free hexagons is 6*21=126, but since they have to be attached (form overlapping molecules sharing edges) the sequence ends already at compounds with 86 carbons.  R. J. Mathar, May 02 2008


REFERENCES

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) pp. 842851. See Table 4 column 5 on page 846.


LINKS

Table of n, a(n) for n=60..73.
G. Brinkmann, G. Caporossi and P. Hansen, A survey and new results on computer enumeration of polyhex and fusene hdyrocarbons, J Chem. Inf Comput. Sci vol 43 no 3 (2003) pp 842851.


EXAMPLE

If n=70 then the number of benzenoids with 21 hexagons with D_(2h) symmetry is 16.
If n=86 then the number of benzenoids with 21 hexagons with D_(2h) symmetry is 40.
Starting value of n is 60 and is even.
For n=10, there are 16 different forms of C_70H_30 of benzenoids of 21 hexagons attached along at least one edge, which each have D_(2h) planar symmetry.


CROSSREFS

Sequence in context: A310030 A045716 A236203 * A310031 A310032 A310033
Adjacent sequences: A122536 A122537 A122538 * A122540 A122541 A122542


KEYWORD

nonn,fini,full


AUTHOR

Parthasarathy Nambi, Sep 18 2006


EXTENSIONS

Edited by R. J. Mathar, May 02 2008


STATUS

approved



