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A216122 The Wiener index of the nanostar dendrimer NS[n], defined pictorially in the Ashrafi et al. reference. 1
94698, 1317858, 10315218, 63835698, 349594098, 1781094258, 8661794418, 40799683698, 187793424498, 849479276658, 3790907541618, 16734956611698, 73223518070898, 318024922835058, 1372613885896818, 5892491154499698, 25178059222493298, 107144508620089458 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1) has been checked by the direct computation of the Wiener index (using Maple).

LINKS

Table of n, a(n) for n=1..18.

A. R. Ashrafi and M. Mirzagar, PI, Szeged and edge Szeged indices of an infinite family of nanostar dendrimers, Indian J. of Chemistry, 47A, 2008, 538-541.

M. Rostami, M. Shabanian, and H. Moghanian, Some topological indices for theoretical study of two types of nanostar dendrimers, Digest J. of Nanomaterials and Biostructures, 7, No. 1, 2012, 247-252.

J. Yang, F. Xia, and S. Chen, Second-order and third-order connectivity indices of an infinite family of dendrimer nanostars, Int. J. Contemp. Math. Sciences, 6, 2011, No. 5, 215-220.

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

FORMULA

a(n) = -55182 + 181020*2^n - 125640*4^n -42000*n*2^n +93600*n*4^n.

G.f.: -6*x*(2112*x^4+10912*x^3-126044*x^2+14464*x+15783) / ((x-1)*(2*x-1)^2*(4*x-1)^2). - Colin Barker, Apr 01 2013

MAPLE

a := proc (n) options operator, arrow: -55182+181020*2^n-125640*4^n+93600*4^n*n-42000*2^n*n end proc: seq(a(n), n = 1 .. 18);

CROSSREFS

Cf. A216123.

Sequence in context: A252323 A030091 A128376 * A206411 A128389 A258420

Adjacent sequences:  A216119 A216120 A216121 * A216123 A216124 A216125

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, Mar 25 2013

STATUS

approved

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Last modified January 23 19:17 EST 2022. Contains 350515 sequences. (Running on oeis4.)