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A224452 The Wiener index of the nanostar dendrimer NS_2[n], defined pictorially in the A. R. Ashrafi et al. reference. 1
198, 2646, 21558, 141686, 825078, 4438006, 22578678, 110311926, 522899958, 2422104566, 11019370998, 49421451766, 219106574838, 962208334326, 4192177750518, 18142557897206, 78066631049718, 334254292599286, 1424972878709238 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(2) and a(3) have been checked by the direct computation of the Wiener index (using Maple).

REFERENCES

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.

LINKS

Table of n, a(n) for n=0..18.

FORMULA

a(n) = 502 + 1280n*4^n + 1120n*2^n + 2000*2^n - 2304*4^n.

G.f.: 2(99 + 36z - 84z^2 + 736z^3 + 1472z^4)/((1-z)(1-2z)^2*(1-4z)^2).

MAPLE

a:= proc(n) options operator, arrow: 502+1280*4^n*n+1120*2^n*n+2000*2^n-2304*4^n end proc: seq(a(n), n = 0 .. 18);

CROSSREFS

Cf. A224453.

Sequence in context: A065697 A159204 A075457 * A227705 A290933 A278017

Adjacent sequences:  A224449 A224450 A224451 * A224453 A224454 A224455

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, Apr 06 2013

STATUS

approved

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Last modified June 15 16:13 EDT 2019. Contains 324142 sequences. (Running on oeis4.)