A221004 The Wiener index of the nanostar dendrimer NS[n], defined pictorially in the Wang-Hua reference.

1437, 4263, 15675, 68163, 325779, 1602483, 7835379, 37613427, 176915571, 816731763, 3710601843, 16633811571, 73738101363, 323845964403, 1411137700467, 6107956052595, 26286286307955, 112564798489203, 479941662081651, 2038504721744499, 8628988563948147, 36415869693198963, 153263217907335795, 643451990789063283, 2695404780741722739, 11268007106608890483

Offset

0,1

Links

Table of n, a(n) for n=0..25.

H. Wang and H. Hua, Computing the second- and third- connectivity index of an infinite class of dendrimer nanostars, Digest J. Nanomaterials and Biostructures, 5 (2010) 497-502.

L. Yang and H. Hua, Modified terminal Wiener index of a type of dendrimer nanostars, Optoelectronics and Advanced Materials - Rapid Communications, 5 (2011) 160-163.

Formula

a(n) = 627 + 2^n*(936*n+1602)+4^n*(432*n-792).

G.f.: 3*(479-4806*x+17408*x^2-25152*x^3+13952*x^4)/((1-x)*(1-2*x)^2*(1-4*x)^2). - Bruno Berselli, Dec 30 2012

Maple

a := proc (n) options operator, arrow: 627+2^n*(936*n+1602)+4^n*(432*n-792) end proc: seq(a(n), n = 0 .. 25);

Crossrefs

Cf. A221005.

Sequence in context: A114083 A143475 A245948 * A204862 A227494 A352249

Adjacent sequences: A221001 A221002 A221003 * A221005 A221006 A221007

Keyword

nonn,easy

Author

Emeric Deutsch, Dec 29 2012

Status

approved