OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Diana Savin and Elif Tan, On Companion sequences associated with Leonardo quaternions: Applications over finite fields, arXiv:2403.01592 [math.CO], 2024. See p. 2.
Index entries for linear recurrences with constant coefficients, signature (2,0,-1).
FORMULA
From Ron Knott, Aug 25 2006: (Start)
G.f.: (1+2*x-2*x^2)/((1-x)*(1-x-x^2)).
a(0)=1, a(1)=4, a(2)=6, a(n) = 2*a(n-1) - a(n-3). (End)
a(n) - a(n-1) = A013655(n-1). - R. J. Mathar, May 06 2014
MATHEMATICA
LinearRecurrence[{2, 0, -1}, {1, 4, 6}, 50] (* G. C. Greubel, Aug 25 2017 *)
PROG
(PARI) x='x+O('x^50); Vec((1+2*x-2*x^2)/((1-x)*(1-x-x^2))) \\ G. C. Greubel, Aug 25 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved