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A107943 (1/8640)*(n+1)*(n+2)^2*(n+3)^2*(n+4)^2*(n+5)*(2*n+3). 0
1, 25, 245, 1470, 6468, 22932, 69300, 185130, 448305, 1002001, 2095093, 4140500, 7796880, 14080080, 24511824, 41314284, 67660425, 107991345, 168413245, 257188162, 385334180, 567352500, 822100500, 1173831750, 1653425865 (list; graph; refs; listen; history; text; internal format)
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. 229).

LINKS

Table of n, a(n) for n=0..24.

FORMULA

G.f.: (1+15*x+40*x^2+25*x^3+3*x^4)/(1-x)^10  - Bruno Berselli, Apr 19 2011

MAPLE

a:=n->(1/8640)*(n+1)*(n+2)^2*(n+3)^2*(n+4)^2*(n+5)*(2*n+3): seq(a(n), n=0..30);

MATHEMATICA

Table[((n+1)(n+2)^2(n+3)^2(n+4)^2(n+5)(2n+3))/8640, {n, 0, 30}]  (* Harvey P. Dale, Apr 19 2011 *)

CROSSREFS

Sequence in context: A160222 A088890 A108178 * A125388 A126546 A023073

Adjacent sequences:  A107940 A107941 A107942 * A107944 A107945 A107946

KEYWORD

nonn

AUTHOR

Emeric Deutsch, Jun 12 2005

STATUS

approved

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Last modified November 27 04:47 EST 2014. Contains 250155 sequences.