OFFSET
0,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,2,4).
FORMULA
From Andrew Howroyd, Jan 03 2020: (Start)
G.f.: 3*x*(1 + x)/((1 - 2*x)*(1 + 2*x + 2*x^2)).
a(n) = 3*A134136(n). (End)
PROG
(PARI) concat([0], Vec(3*(1 + x)/((1 - 2*x)*(1 + 2*x + 2*x^2)) + O(x^40))) \\ Andrew Howroyd, Jan 03 2020
(Magma) a:=[0, 3, 3]; [n le 3 select a[n] else 2*Self(n-2) + 4*Self(n-3):n in [1..35]]; // Marius A. Burtea, Jan 03 2020
(Magma) R<x>:=PowerSeriesRing(Integers(), 35); [0] cat Coefficients(R!( 3*x*(1 + x)/((1 - 2*x)*(1 + 2*x + 2*x^2)))); // Marius A. Burtea, Jan 03 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Curtz, Jan 29 2008
EXTENSIONS
a(12) corrected and terms a(13) and beyond from Andrew Howroyd, Jan 03 2020
STATUS
approved