A121212 - OEIS

A121212

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

0, 0, 0, 0, 0, 1, 1, 0, 5, 5, 0, 21, 26, 0, 95, 118, 0, 423, 543, 0, 1923, 2507, 0, 8869, 11676, 0, 41410, 54893, 0, 195353, 260220, 0, 929423, 1242820, 0

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OFFSET

1,9

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 C_(3h) column.

LINKS

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

CROSSREFS

Sequence in context: A233383 A144184 A119380 * A182787 A133337 A279932

Adjacent sequences: A121209 A121210 A121211 * A121213 A121214 A121215

KEYWORD

nonn

AUTHOR

Parthasarathy Nambi, Aug 19 2006

STATUS

approved