OFFSET
0,1
COMMENTS
a(n) is the number of vertices in the second type dendrimer nanostar NS2[n], defined pictorially in the Chen et al. reference (Fig. 1).
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
S. Chen and J. Yang, Second-order and third-order connectivity indices of dendrimer nanostars, International Mathematical Forum, 6, No, 5, 2011, 223-228.
Index entries for linear recurrences with constant coefficients, signature (3,-2).
FORMULA
G.f.: 6*(1+2*x)/((1-x)*(1-2*x)). - Vincenzo Librandi, May 27 2018
a(n) = 3*a(n-1) - 2*a(n-2) for n>1. - Colin Barker, May 27 2018
MAPLE
seq(24*2^n-18, n=0..40);
MATHEMATICA
Table[24 2^n - 18, {n, 0, 33}] (* Vincenzo Librandi, May 27 2018 *)
PROG
(Magma) [24*2^n - 18: n in [0..33]]; // Vincenzo Librandi, May 27 2018
(PARI) Vec(6*(1 + 2*x) / ((1 - x)*(1 - 2*x)) + O(x^50)) \\ Colin Barker, May 27 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, May 27 2018
STATUS
approved