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A224427
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The Wiener index of the dendrimer NS[n], defined pictorially in the A. R. Ashrafi et al. reference.
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1
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343, 8967, 88679, 620839, 3667623, 19657127, 99084199, 479187879, 2250222503, 10338917287, 46716074919, 208322526119, 919156226983, 4020155841447, 17454879996839, 75316812315559, 323256950193063, 1380987667741607, 5875792265345959
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OFFSET
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0,1
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COMMENTS
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a(1) has been checked by the direct computation of the Wiener index (using Maple).
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REFERENCES
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A. R. Ashrafi and M. Mirzargar, The study of an infinite class of dendrimer nanostars by topological index approaches, J. Appl. Math. Comput, 31, 2009, 289-294.
M. J. Nadjafi-Arani, A new algorithm for computing the Wiener index of molecular graphs (unpublished paper).
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LINKS
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FORMULA
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a(n) = -1113 + 8112*2^n - 6656*4^n + 5120*n*4^n.
G.f.: (343+5194*x+4448*x^2+32*x^3)/((1-x)*(1-2*x)*(1-4*x)^2). [Bruno Berselli, Apr 06 2013]
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MAPLE
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a := proc (n) options operator, arrow: -1113+8112*2^n+5120*4^n*n-6656*4^n end proc: seq(a(n), n = 0 .. 18);
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MATHEMATICA
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CoefficientList[Series[(343 + 5194 x + 4448 x^2 + 32 x^3)/((1 - x) (1 - 2 x) (1 - 4 x)^2), {x, 0, 20}], x] (* Bruno Berselli, Apr 06 2013 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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