

A108646


a(n) = (n+1)(n+2)^2*(n+3)(11n^3 + 58n^2 + 101n + 60)/720.


0



1, 23, 194, 985, 3668, 11074, 28728, 66438, 140415, 276001, 511082, 900263, 1519882, 2473940, 3901024, 5982300, 8950653, 13101051, 18802210, 26509637, 36780128, 50287798, 67841720, 90405250, 119117115, 155314341, 200557098
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OFFSET

0,2


COMMENTS

KekulĂ© numbers for certain benzenoids.


REFERENCES

S. J. Cyvin and I. Gutman, KekulĂ© structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 230, no. 22).


LINKS

Table of n, a(n) for n=0..26.


MAPLE

a:=(n+1)*(n+2)^2*(n+3)*(11*n^3+58*n^2+101*n+60)/720: seq(a(n), n=0..30);


CROSSREFS

Sequence in context: A160083 A140545 A062640 * A058193 A065314 A065316
Adjacent sequences: A108643 A108644 A108645 * A108647 A108648 A108649


KEYWORD

nonn


AUTHOR

Emeric Deutsch, Jun 13 2005


STATUS

approved



