OFFSET
0,1
COMMENTS
a(n) is the number of edges in the dendrimer nanostar G[n], defined pictorially in the Iranmanesh et al. reference (Fig. 1, where G[3] is shown) or in Alikhani et al. reference (Fig. 1, where G[3] is shown).
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
S. Alikhani, M. A. Iranmanesh, Eccentric connectivity polynomials of an infinite family of dendrimer, Digest J. Nanomaterials and Biostructures, 6 (2011) 253-257.
A. Iranmanesh and N. Dorosti, Computing the Cluj index of a type dendrimer nanostars, MATCH Commun. Math. Comput. Chem. 65, 2011, 209-219.
Index entries for linear recurrences with constant coefficients, signature (3,-2).
FORMULA
From Colin Barker, May 25 2018: (Start)
G.f.: 24 / ((1 - x)*(1 - 2*x)).
a(n) = 3*a(n-1) - 2*a(n-2) for n>1.
(End)
MAPLE
seq(48*2^n - 24, n = 0 .. 40);
PROG
(PARI) Vec(24 / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ Colin Barker, May 25 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, May 25 2018
STATUS
approved