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A224461 The Wiener index of Wang's helicene-based dendrimer defined pictorially as DNS_2[n] in the Shabani et al. reference. 1
1636, 35877, 358267, 2593671, 15836671, 87269679, 449795599, 2213852367, 10541202511, 48969228111, 223231118671, 1002642454863, 4450100228431, 19559951884623, 85281094811983, 369296144564559, 1589885770858831, 6810377914286415, 29044914697011535, 123393405571563855 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
REFERENCES
H. Shabani, A. R. Ashrafi, I. Gutman, Geometric-arithmetic index: an algebraic approach, Studia UBB, Chemia, LV, 2010, 107-112.
LINKS
FORMULA
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).
MAPLE
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);
CROSSREFS
Cf. A224462.
Sequence in context: A072409 A052455 A252619 * A233121 A054808 A218010
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jul 12 2013
STATUS
approved

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Last modified April 17 15:33 EDT 2024. Contains 371764 sequences. (Running on oeis4.)