A120386 - OEIS

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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

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OFFSET

54,2

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.

REFERENCES

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

LINKS

Table of n, a(n) for n=54..66.

EXAMPLE

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.

CROSSREFS

Cf. A018190.

Sequence in context: A273949 A174285 A227427 * A061982 A101562 A034566

Adjacent sequences: A120383 A120384 A120385 * A120387 A120388 A120389

KEYWORD

nonn

AUTHOR

Parthasarathy Nambi, Aug 27 2006

STATUS

approved