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A109119 a(n) = 2(5n^2 + 5n + 1)^3. 0

%I #9 Jul 22 2022 09:35:42

%S 2,2662,59582,453962,2060602,6885902,18787862,44376082,94091762,

%T 183467702,334568302,577609562,952759082,1512116062,2321871302,

%U 3464647202,5042017762,7177208582,10017976862,13739671402,18548472602

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

%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).

%F G.f.: 2(1 + 1324z + 20495z^2 + 46360z^3 + 20495z^4 + 1324z^5 + z^6)/(1-z)^7.

%F a(n) = 2*A062786(n)^3. - _R. J. Mathar_, Jul 22 2022

%p a:=n->2*(5*n^2+5*n+1)^3: seq(a(n),n=0..28);

%K nonn,easy

%O 0,1

%A _Emeric Deutsch_, Jun 19 2005

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)