A121211 Number of free hexagonal polygons of symmetry class D_(2h) and area n.

0, 1, 1, 2, 2, 3, 3, 6, 7, 11, 14, 21, 23, 41, 50, 80, 94, 156, 189, 310, 365, 615, 748, 1237, 1459, 2488, 3023, 5059, 5994, 10296, 12511, 21149, 25100, 43451, 52870

Offset

1,4

References

Markus Voege, Anthony J. Guttmann and Iwan Jensen, "On the number of benzenoid hydrocarbons", J. Chem. Inf. Comput. Sci., (2002), vol. 42, 456-466. See Table 3 under the D_(2h) column.

Links

Table of n, a(n) for n=1..35.

Example

If n=10 then the number of free hexagonal polygons of symmetry class D_(2h) is 11 which is the tenth term in the sequence.

Crossrefs

Sequence in context: A054172 A236971 A373446 * A316585 A369765 A146157

Adjacent sequences: A121208 A121209 A121210 * A121212 A121213 A121214

Keyword

nonn

Author

Parthasarathy Nambi, Aug 19 2006

Status

approved