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%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