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%I #8 Jul 22 2022 11:30:48
%S 84,18327,233565,1771209,10839249,59193537,301745505,1470068769,
%T 6938902689,32002414497,145020899745,648175476129,2865160922529,
%U 12550658135457,54563037754785,235694448080289,1012548295652769,4329277751424417,18433454242526625
%N The Wiener index of the dendrimer D_1[n], defined pictorially in the A. R. Ashrafi et al. reference.
%C a(2) has 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.
%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (13,-64,148,-160,64).
%F a(n) = - 2655 + 26907*2^n + 16245*n*4^n -24168*4^n -570*n*2^n.
%F G.f. = 3(28+5745z+230z^2-34880z^3+20912z^4)/[(1-z)(1-2z)^2*(1-4z)^2].
%p a := proc (n) options operator, arrow: -2655+26907*2^n+16245*4^n*n-24168*4^n-570*2^n*n end proc: seq(a(n), n = 0 .. 18);
%Y Cf. A224430
%K nonn,easy
%O 0,1
%A _Emeric Deutsch_, Apr 06 2013