A304606 a(n) = 54*2^n + 28 (n >= 1).

136, 244, 460, 892, 1756, 3484, 6940, 13852, 27676, 55324, 110620, 221212, 442396, 884764, 1769500, 3538972, 7077916, 14155804, 28311580, 56623132, 113246236, 226492444, 452984860, 905969692, 1811939356, 3623878684, 7247757340, 14495514652, 28991029276, 57982058524

Offset

1,1

Comments

a(n) is the number of edges of the nanostar dendrimer G[n] from the Ashrafi et al. reference.

Links

Colin Barker, Table of n, a(n) for n = 1..1000

A. R. Ashrafi, A. Karbasioun, and M. V. Diudea, Computing Wiener and detour indices of a new type of nanostar dendrimers, MATCH Commun. Math. Comput. Chem. 65, 2011, 193-200.

Index entries for linear recurrences with constant coefficients, signature (3,-2).

Formula

From Michael De Vlieger, May 16 2018: (Start)

G.f.: 4*x*(34 - 41*x)/(1 - 3*x + 2*x^2).

a(n) = 3*a(n - 1) - 2*a(n - 2) for n > 2. (End)

Maple

seq(54*2^n+28, n = 1 .. 40);

Mathematica

CoefficientList[Series[4 (34 - 41 x)/(1 - 3 x + 2 x^2), {x, 0, 33}], x] (* or *)
LinearRecurrence[{3, -2}, {136, 244}, 34] (* or *)
Array[54*2^# + 28 &, 34] (* Michael De Vlieger, May 16 2018 *)

Prog

(PARI) a(n) = 54*2^n + 28; \\ Altug Alkan, May 15 2018
(PARI) Vec(4*x*(34 - 41*x)/(1 - 3*x + 2*x^2) + O(x^40)) \\ Colin Barker, May 23 2018
(GAP) List([1..40], n->54*2^n+28); # Muniru A Asiru, May 16 2018

Crossrefs

Cf. A304605, A304607, A304608.

Sequence in context: A235285 A391530 A282794 * A264951 A264958 A262615

Adjacent sequences: A304603 A304604 A304605 * A304607 A304608 A304609

Keyword

nonn,easy

Author

Emeric Deutsch, May 15 2018

Status

approved