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A109116 a(n) = (n+1)^3*(n+2)^2*(n+5). 1
20, 432, 3024, 12800, 40500, 105840, 241472, 497664, 947700, 1694000, 2874960, 4672512, 7320404, 11113200, 16416000, 23674880, 33428052, 46317744, 63102800, 84672000, 112058100, 146452592, 189221184, 241920000, 306312500, 384387120 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Kekulé numbers for certain benzenoids.

REFERENCES

S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 310).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

FORMULA

G.f.: 4(5 + 73z + 105z^2 + z^3 - 4z^4)/(1-z)^7.

MAPLE

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

MATHEMATICA

Table[(n+1)^3 (n+2)^2 (n+5), {n, 0, 30}] (* Harvey P. Dale, Sep 24 2011 *)

PROG

(MAGMA) [(n+1)^3*(n+2)^2*(n+5): n in [0..30]]; // Vincenzo Librandi, Sep 25 2011

CROSSREFS

Sequence in context: A215290 A130832 A180810 * A190922 A136257 A320765

Adjacent sequences:  A109113 A109114 A109115 * A109117 A109118 A109119

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, Jun 19 2005

STATUS

approved

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Last modified June 1 20:49 EDT 2020. Contains 334765 sequences. (Running on oeis4.)