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,-2).
FORMULA
a(n) = (-1)^n * A077943(n). - R. J. Mathar, Aug 04 2008
MATHEMATICA
LinearRecurrence[{-2, -2, -2}, {1, -2, 2}, 50] (* or *) CoefficientList[ Series[1/(1+2*x+2*x^2+2*x^3), {x, 0, 50}], x] (* G. C. Greubel, Jun 27 2019 *)
PROG
(PARI) my(x='x+O('x^50)); Vec(1/(1+2*x+2*x^2+2*x^3)) \\ G. C. Greubel, Jun 27 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/(1+2*x+2*x^2+2*x^3) )); // G. C. Greubel, Jun 27 2019
(Sage) (1/(1+2*x+2*x^2+2*x^3)).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Jun 27 2019
(GAP) a:=[1, -2, 2];; for n in [4..50] do a[n]:=-2*(a[n-1]+a[n-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