OFFSET
0,5
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,-1,-2).
MATHEMATICA
LinearRecurrence[{2, -1, -2}, {1, 1, 1}, 40] (* or *) CoefficientList[ Series[(1-x)/(1-2*x+x^2+2*x^3), {x, 0, 40}], x] (* G. C. Greubel, Jun 27 2019 *)
PROG
(PARI) my(x='x+O('x^40)); Vec((1-x)/(1-2*x+x^2+2*x^3)) \\ G. C. Greubel, Jun 27 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1-x)/( 1-2*x+x^2+2*x^3) )); // G. C. Greubel, Jun 27 2019
(Sage) ((1-x)/(1-2*x+x^2+2*x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Jun 27 2019
(GAP) a:=[1, 1, 1];; for n in [4..40] do a[n]:=2*a[n-1]-a[n-2]-2*a[n-3]; od; a; # G. C. Greubel, Jun 27 2019
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved