

A108677


(n+1)(n+2)(n+3)(n+4)(19n^2+47n+30)/720.


0



1, 16, 100, 399, 1218, 3108, 6972, 14190, 26763, 47476, 80080, 129493, 202020, 305592, 450024, 647292, 911829, 1260840, 1714636, 2296987, 3035494, 3961980, 5112900, 6529770, 8259615, 10355436, 12876696, 15889825, 19468744, 23695408
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OFFSET

0,2


COMMENTS

Kekule numbers for certain benzenoids.


REFERENCES

S. J. Cyvin and I. Gutman, Kekule structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p.231, # 41).


LINKS

Table of n, a(n) for n=0..29.


FORMULA

G.f.=(1+9z+9z^2)/(1z)^7.


MAPLE

a:=n>(n+1)*(n+2)*(n+3)*(n+4)*(19*n^2+47*n+30)/720: seq(a(n), n=0..33);


MATHEMATICA

Table[(n+1)(n+2)(n+3)(n+4)(19n^2+47n+30)/720, {n, 0, 40}] (* Harvey P. Dale, Mar 04 2011 *)


CROSSREFS

Sequence in context: A014762 A045784 A016958 * A001249 A014796 A052206
Adjacent sequences: A108674 A108675 A108676 * A108678 A108679 A108680


KEYWORD

nonn


AUTHOR

Emeric Deutsch, Jun 17 2005


STATUS

approved



