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A224433
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The Wiener index of the dendrimer D_3[n], defined pictorially in the A. R. Ashrafi et al. reference.
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1
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174, 22734, 299646, 2332398, 14462574, 79461294, 406098606, 1980213678, 9348000174, 43104718254, 195270696366, 872477232558, 3855431404974, 16883645533614, 73381802986926, 316914939973038, 1361207885548974, 5819017520467374, 24772799043194286
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OFFSET
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0,1
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COMMENTS
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a(0) and a(1) have 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 H. Shabani, Computing Padmakar-Ivan index of four classes of dendrimers, Bulgarian Chem. Comm., 44, N0. 2, 2012, 127-130.
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LINKS
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FORMULA
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a(n)=-12882+44604*2^n-31548*4^n+21780*n*4^n-7260*n*2^n.
G.f.=(6*(29+3412*z+2540*z^2-22296*z^3-3008*z^4))/[(1-z)*(1-2*z)^2*(1-4*z)^2]
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MAPLE
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a := proc (n) options operator, arrow: -12882+44604*2^n-31548*4^n+21780*4^n*n-7260*2^n*n end proc: seq(a(n), n = 0 .. 18);
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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