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A224461
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The Wiener index of Wang's helicene-based dendrimer defined pictorially as DNS_2[n] in the Shabani et al. reference.
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1
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1636, 35877, 358267, 2593671, 15836671, 87269679, 449795599, 2213852367, 10541202511, 48969228111, 223231118671, 1002642454863, 4450100228431, 19559951884623, 85281094811983, 369296144564559, 1589885770858831, 6810377914286415, 29044914697011535, 123393405571563855
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OFFSET
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1,1
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REFERENCES
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H. Shabani, A. R. Ashrafi, I. Gutman, Geometric-arithmetic index: an algebraic approach, Studia UBB, Chemia, LV, 2010, 107-112.
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LINKS
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FORMULA
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a(n) = 335 + 2^n*(6858*n+37319/2)+4^n*(6561*n-37989/2).
G.f.: x*(1636+14609*x-3430*x^2-9800*x^3)/((1-x)*(1-2*x)^2*(1-4*x)^2).
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MAPLE
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a:= proc (n) options operator, arrow: 335+2^n*(6858*n+37319/2)+4^n*(6561*n-37989/2) end proc: seq(a(n), n = 1 .. 20);
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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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