%I #7 Feb 27 2015 22:48:03

%S 730,8002,60754,381490,2146930,11252722,56133874,270161650,1265842930,

%T 5810393842,26243850994,117016314610,516299391730,2258288837362,

%U 9805857424114,42314967024370,181627585561330,775984568599282,3301842333205234

%N The Wiener index of the nanostar dendrimer NS_1[n], defined pictorially in the A. R. Ashrafi et al. reference.

%C a(1) has been checked by the direct computation of the Wiener index (using Maple).

%D A. R. Ashrafi and P. Nikzad, Kekulé index and bounds of energy for nanostar dendrimers, Digest J. of Nanomaterials and Biostructures, 4, No. 2, 2009, 383-388.

%F a(n) = -754 + 3768*2^n + 2880n*4^n + 1680n*2^n - 3792*4^n.

%F G.f.: 2(365 - 744z + 1724z^2 - 2112z^3 + 4160z^4)/((1-z)(1-2z)^2*(1-4z)^2).

%p a := proc (n) options operator, arrow: 754+1680*2^n*n+2880*4^n*n-3792*4^n+3768*2^n end proc: seq(a(n), n = 0 .. 18);

%Y Cf. A224438.

%K nonn

%O 0,1

%A _Emeric Deutsch_, Apr 06 2013