A221050 The Wiener index of the nanostar dendrimer D_1[n], defined pictorially in the Eslahchi et al. reference.

42, 1008, 10276, 75180, 462140, 2558556, 13231260, 65284380, 311431708, 1448846364, 6612207644, 29725724700, 132031520796, 580686331932, 2533085184028, 10973912563740, 47262391730204, 202517499871260, 863943782826012, 3671274602627100, 15547105441480732

Offset

0,1

References

Ch. Eslahchi, S. Alikhani, M. H. Akhbari, Hosoya polynomial of an infinite family of dendrimer nanostar, Iranian J. Math. Chem. 2 (2011) 71-79.

Links

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

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

Formula

a(n) = 28+2^n*(448*n+1554)+4^n*(784*n-1540). Theorem 5 of the Eslahchi et al. paper contains a less explicit formula for the Wiener index.

G.f.: 14*(3+33*x-10*x^2-8*x^3)/((1-x)*(1-2*x)^2*(1-4*x)^2). - Bruno Berselli, Dec 30 2012

Maple

a := proc (n) options operator, arrow: 28+2^n*(448*n+1554)+4^n*(784*n-1540) end proc: seq(a(n), n = 0 .. 20);

Crossrefs

Cf. A221051.

Sequence in context: A020932 A264489 A036400 * A050988 A163741 A140404

Adjacent sequences: A221047 A221048 A221049 * A221051 A221052 A221053

Keyword

nonn,easy

Author

Emeric Deutsch, Dec 30 2012

Extensions

Offset changed from 1 to 0 by Bruno Berselli, Dec 30 2012

Status

approved