A221002 The Wiener index of the nanostar dendrimer G[n], defined pictorially in the Karbasioun-Ashrafi reference.

21558, 141686, 825078, 4438006, 22578678, 110311926, 522899958, 2422104566, 11019370998, 49421451766, 219106574838, 962208334326, 4192177750518, 18142557897206, 78066631049718, 334254292599286, 1424972878709238, 6051724204704246, 25614248465924598, 108086444576211446, 454863674100679158

Offset

0,1

Links

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

A. Karbasioun and A. R. Ashrafi, Wiener and detour indices of a new type of nanostar dendrimers, Macedonian J. of Chemistry and Chemical Engineering 28 (2009) 49-54.

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

Formula

a(n) = 502 + 2^(n+6)*5*(14*n+53)+4^(n+6)*(5n+1).

G.f.: -2*(84672*x^4-205344*x^3+181436*x^2-69284*x+10779) / ((x-1)*(2*x-1)^2*(4*x-1)^2). [Colin Barker, Jan 01 2013]

Maple

a := proc (n) options operator, arrow: 502+5*2^(n+6)*(14*n+53)+4^(n+6)*(5*n+1) end proc; :seq(a(n), n = 0 .. 20);

Mathematica

LinearRecurrence[{13, -64, 148, -160, 64}, {21558, 141686, 825078, 4438006, 22578678}, 30] (* Harvey P. Dale, Jul 20 2019 *)

Crossrefs

Cf. A221003.

Sequence in context: A063388 A252393 A211236 * A190470 A113620 A074812

Adjacent sequences: A220999 A221000 A221001 * A221003 A221004 A221005

Keyword

nonn,easy

Author

Emeric Deutsch, Dec 28 2012

Status

approved