OFFSET
0,1
COMMENTS
a(n) is the number of edges of the nanostar dendrimer G[n], shown pictorially as NSD[n] in the Rostami et al. reference (Fig. 2).
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
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, Vol. 7, No. 1 (2012), 247-252.
Index entries for linear recurrences with constant coefficients, signature (3,-2).
FORMULA
From Colin Barker, May 31 2018: (Start)
G.f.: (13 + 114*x) / ((1 - x)*(1 - 2*x)).
a(n) = 3*a(n-1) - 2*a(n-2) for n>1.
(End)
MAPLE
seq(140*2^n-127, n = 0 .. 40);
PROG
(PARI) a(n) = 140*2^n - 127 \\ Felix Fröhlich, May 29 2018
(PARI) Vec((13 + 114*x) / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ Colin Barker, May 31 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, May 29 2018
STATUS
approved