OFFSET
0,1
COMMENTS
a(n) (n>=1) is the number of vertices of the first type of dendrimer nanostar G[n], shown pictorially in the Iranmanesh et al. reference (Fig. 1).
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
A. Iranmanesh, N. A. Gholami, Computing the Szeged index of two type dendrimer nanostars, Croatica Chemica Acta, 81, No. 2, 2008, 299-303.
Index entries for linear recurrences with constant coefficients, signature (3,-2).
FORMULA
From Colin Barker, May 30 2018: (Start)
G.f.: 2*(37 - 68*x) / ((1 - x)*(1 - 2*x)).
a(n) = 3*a(n-1) - 2*a(n-2) for n>1.
(End)
MAPLE
seq(12*2^n+62, n = 0..40);
MATHEMATICA
Table[12*2^n+62, {n, 0, 50}] (* or *) LinearRecurrence[{3, -2}, {74, 86}, 50] (* Harvey P. Dale, Jun 23 2020 *)
PROG
(PARI) Vec(2*(37 - 68*x) / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ Colin Barker, May 30 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, May 29 2018
STATUS
approved