Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #9 Nov 15 2016 03:02:36
%S 2192,75884,811076,5876276,35361428,191654996,973156820,4730314964,
%T 22295250644,102723642068,465158748884,2077879380692,9180871101140,
%U 40201652095700,174720788384468,754542896859860,3240816616917716
%N The Wiener index of the nanostar dendrimer NSC_5C_6[n], defined pictorially in the Ashrafi et al. and the Rostami et al. references.
%C a(2) has been checked by the direct computation of the Wiener index (using Maple).
%H A. R. Ashrafi and P. Nikzad, <a href="http://www.chalcogen.ro/1Ashrafi-Nikzad.pdf">Szeged index of nanostar dendrimers</a>, Digest J. of Nanomaterials and Biostructures, 4, No. 1, 2009, 155-157.
%H M. Rostami, M. Shabanian, and H. Moghanian, <a href="http://www.chalcogen.ro/247_Rostami.pdf">Some topological indices for theoretical study of two types of nanostar dendrimers</a>, Digest J. of Nanomaterials and Biostructures, 7, No. 1, 2012, 247-252.
%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) = -13612 + 2^n*(72*n + 45270) + 4^n*(12960*n - 31680).
%F G.f. = 4*z*(548 + 11847*z -8782*z^2 - 33888*z^3 - 352*z^4)/((1-z)*(1-2*z)^2*(1-4*z)^2).
%p a := proc (n) options operator, arrow: -13612+2^n*(72*n+45270)+4^n*(12960*n-31680) end proc: seq(a(n), n = 1 .. 20);
%Y Cf. A227489
%K nonn,easy
%O 1,1
%A _Emeric Deutsch_, Jul 16 2013