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%I #6 Apr 07 2013 02:42:34
%S 174,22734,299646,2332398,14462574,79461294,406098606,1980213678,
%T 9348000174,43104718254,195270696366,872477232558,3855431404974,
%U 16883645533614,73381802986926,316914939973038,1361207885548974,5819017520467374,24772799043194286
%N The Wiener index of the dendrimer D_3[n], defined pictorially in the A. R. Ashrafi et al. reference.
%C a(0) and a(1) have been checked by the direct computation of the Wiener index (using Maple).
%D A. R. Ashrafi and H. Shabani, Computing Padmakar-Ivan index of four classes of dendrimers, Bulgarian Chem. Comm., 44, N0. 2, 2012, 127-130.
%F a(n)=-12882+44604*2^n-31548*4^n+21780*n*4^n-7260*n*2^n.
%F 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]
%p 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);
%Y Cf. A224434
%K nonn
%O 0,1
%A _Emeric Deutsch_, Apr 06 2013