login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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. 842-851. 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 842-851.

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: A218485 A045716 A236203 * A023660 A161339 A023562

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 10 15:32 EST 2016. Contains 279003 sequences.