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A109116 a(n) = (n+1)^3*(n+2)^2*(n+5). 1

%I

%S 20,432,3024,12800,40500,105840,241472,497664,947700,1694000,2874960,

%T 4672512,7320404,11113200,16416000,23674880,33428052,46317744,

%U 63102800,84672000,112058100,146452592,189221184,241920000,306312500,384387120

%N a(n) = (n+1)^3*(n+2)^2*(n+5).

%C Kekulé numbers for certain benzenoids.

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

%H Vincenzo Librandi, <a href="/A109116/b109116.txt">Table of n, a(n) for n = 0..10000</a>

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

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

%t Table[(n+1)^3 (n+2)^2 (n+5),{n,0,30}] (* _Harvey P. Dale_, Sep 24 2011 *)

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

%K nonn,easy

%O 0,1

%A _Emeric Deutsch_, Jun 19 2005

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Last modified July 11 15:58 EDT 2020. Contains 335626 sequences. (Running on oeis4.)