A304168 a(n) = 2*3^n - 2^(n-1) (n>=1).
5, 16, 50, 154, 470, 1426, 4310, 12994, 39110, 117586, 353270, 1060834, 3184550, 9557746, 28681430, 86060674, 258214790, 774709906, 2324260790, 6973044514, 20919657830, 62760022066, 188282163350, 564850684354, 1694560441670, 5083698102226, 15251127861110, 45753450692194, 137260486294310, 411781727318386
Offset: 1
Links
- Colin Barker, Table of n, a(n) for n = 1..1000
- D. Antony Xavier, M. Rosary, and Andrew Arokiaraj, Topological properties of Sierpinski Gasket Rhombus graphs, International J. of Mathematics and Soft Computing, 4, No. 2, 2014, 95-104.
- Index entries for linear recurrences with constant coefficients, signature (5,-6).
Programs
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GAP
List([1..35],n->2*3^n-2^(n-1)); # Muniru A Asiru, May 10 2018
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Maple
seq(2*3^n-2^(n-1), n = 1 .. 40);
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PARI
Vec(x*(5 - 9*x) / ((1 - 2*x)*(1 - 3*x)) + O(x^30)) \\ Colin Barker, May 10 2018
Formula
From Colin Barker, May 10 2018: (Start)
G.f.: x*(5 - 9*x) / ((1 - 2*x)*(1 - 3*x)).
a(n) = 5*a(n-1) - 6*a(n-2) for n>2.
(End)
Comments