A221008 The Wiener index of the nanostar dendrimer D_3[n] , defined pictorially in the Alikhani - Iranmanesh reference.

1026, 19458, 174762, 1170810, 6751386, 35653338, 177967962, 854830170, 3994246746, 18282889818, 82367580762, 366439242330, 1613682326106, 7046530103898, 30553522371162, 131684094835290, 564617195813466, 2409993639295578, 10246077161667162, 43408725425257050, 183332581536692826

Offset

0,1

Links

Table of n, a(n) for n=0..20.

S. Alikhani and M. A. Iranmanesh, Eccentric connectivity polynomials of an infinite family of dendrimer, Digest J. Nanomaterials and Biostructures, 6 (2011) 253-257.

Index entries for linear recurrences with constant coefficients, signature (11,-42,64,-32).

Formula

a(n) = -1446 + 2^n*12132+4^n*(8820*n-9660).

G.f.: 18*(57+454*x+212*x^2)/((1-x)*(1-2*x)*(1-4*x)^2). - Bruno Berselli, Dec 30 2012

Maple

a := proc (n) options operator, arrow: -1446+12132*2^n+4^n*(8820*n-9660) end proc: seq(a(n), n = 0 .. 20);

Crossrefs

Cf. A221009.

Sequence in context: A031530 A004607 A361811 * A282254 A229332 A253710

Adjacent sequences: A221005 A221006 A221007 * A221009 A221010 A221011

Keyword

nonn,easy

Author

Emeric Deutsch, Dec 29 2012

Status

approved