OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-2,-2,1).
FORMULA
a(n) = (-1)^n*A077944(n).
MATHEMATICA
CoefficientList[Series[1/(1+2x+2x^2-x^3), {x, 0, 40}], x] (* or *) LinearRecurrence[ {-2, -2, 1}, {1, -2, 2}, 40] (* Harvey P. Dale, Aug 17 2017 *)
PROG
(PARI) my(x='x+O('x^40)); Vec(1/(1+2*x+2*x^2-x^3)) \\ G. C. Greubel, Jun 26 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1/(1+2*x+2*x^2-x^3) )); // G. C. Greubel, Jun 26 2019
(Sage) (1/(1+2*x+2*x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Jun 26 2019
(GAP) a:=[1, -2, 2];; for n in [4..40] do a[n]:=-2*a[n-1]-2*a[n-2]+a[n-3]; od; a; # G. C. Greubel, Jun 26 2019
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved