A130914 The number of Kekulé structures of the rhombus-shaped benzenoid hydrocarbons.

2, 6, 20, 70, 252, 894, 3432, 12870, 48620, 149226

Offset

1,1

Comments

Here n is the number of aromatic sextets.

References

I. Gutman, N. Turkovic and B. Furtula, "On distribution of pi electrons in rhombus-shaped benzenoid hydrocarbons", Indian Journal of Chemistry, Vol. 45A (2006), pp. 1601-1604. See Table 1 on page 1602.

Links

Table of n, a(n) for n=1..10.

Example

If n=1 then the number of Kekulé structures of the rhombus-shaped benzenoid hydrocarbons is 2.
If n=2 then the number of Kekulé structures of the rhombus-shaped benzenoid hydrocarbons is 6.
If n=3 then the number of Kekulé structures of the rhombus-shaped benzenoid hydrocarbons is 20.

Crossrefs

Sequence in context: A360295 A224514 A065345 * A302644 A087944 A056616

Adjacent sequences: A130911 A130912 A130913 * A130915 A130916 A130917

Keyword

nonn

Author

Parthasarathy Nambi, Aug 23 2007

Status

approved