A224463 - OEIS

%I #14 Aug 19 2021 06:26:09

%S 11095,357449,3692349,26206373,155494901,834211733,4203722965,

%T 20315383637,95323077717,437644252757,1976168966741,8807356781141,

%U 38840665809493,169808425140821,737017916129877,3179209969369685,13641394194809429,58263792669360725

%N The Wiener index of the tetrathiafulvalene dendrimer defined pictorially as D[n] in the Shabani reference.

%H H. Shabani, <a href="https://dx.doi.org/10.22052/ijmc.2010.5143">Computing vertex PI index of tetrathiafulvalene dendrimers</a>, Iranian J. Math. Chem., 1, 2010, 125-130.

%F a(n) = -64939 + 2^n*(-27280*n+344122) + 4^n*(215264*n-268088).

%F G.f.: (11095 + 213214*z - 244408*z^2 - 559488*z^3 - 4864*z^4)/((1-z)*(1-2*z)^2*(1-4*z)^2).

%p a := proc (n) options operator, arrow: -64939+2^n*(-27280*n+344122)+4^n*(215264*n-268088) end proc: seq(a(n), n = 0 .. 20);

%t CoefficientList[Series[(11095 + 213214*x - 244408*x^2 - 559488*x^3 - 4864*x^4) / ((1-x)*(1-2*x)^2*(1-4*x)^2), {x,0,64}], x] (* _Georg Fischer, Aug 18 2021 *)

%Y Cf. A224464.

%K nonn

%O 0,1

%A _Emeric Deutsch_, Jul 12 2013