A224463 The Wiener index of the tetrathiafulvalene dendrimer defined pictorially as D[n] in the Shabani reference.

11095, 357449, 3692349, 26206373, 155494901, 834211733, 4203722965, 20315383637, 95323077717, 437644252757, 1976168966741, 8807356781141, 38840665809493, 169808425140821, 737017916129877, 3179209969369685, 13641394194809429, 58263792669360725

Offset

0,1

Links

Table of n, a(n) for n=0..17.

Hossein Shabani, Computing vertex PI index of tetrathiafulvalene dendrimers, Iranian J. Math. Chem., 1, 2010, 125-130.

Index entries for linear recurrences with constant coefficients, signature (13,-64,148,-160,64).

Formula

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

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

Maple

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);

Mathematica

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, 20}], x] (* Georg Fischer, Aug 18 2021 *)

Crossrefs

Cf. A224464.

Sequence in context: A032427 A204758 A211686 * A300562 A253378 A253371

Adjacent sequences: A224460 A224461 A224462 * A224464 A224465 A224466

Keyword

nonn,easy

Author

Emeric Deutsch, Jul 12 2013

Status

approved