OFFSET
0,4
LINKS
Index entries for linear recurrences with constant coefficients, signature (-1,0,-2).
FORMULA
a(0)=1, a(1)=-1, a(2)=1, a(n)=a(n-1)-2*a(n-3). - Harvey P. Dale, Aug 29 2012
MATHEMATICA
CoefficientList[Series[1/(1+x+2*x^3), {x, 0, 45}], x] (* or *) LinearRecurrence[ {-1, 0, -2}, {1, -1, 1}, 45] (* Harvey P. Dale, Aug 29 2012 *)
PROG
(PARI) Vec(1/(1+x+2*x^3)+O(x^45)) \\ Charles R Greathouse IV, Sep 26 2012
(Magma) R<x>:=PowerSeriesRing(Integers(), 45); Coefficients(R!( 1/(1+x+2*x^3) )); // G. C. Greubel, Jun 25 2019
(Sage) (1/(1+x+2*x^3)).series(x, 45).coefficients(x, sparse=False) # G. C. Greubel, Jun 25 2019
(GAP) a:=[1, -1, 1];; for n in [4..45] do a[n]:=-a[n-1]-2*a[n-3]; od; a; # G. C. Greubel, Jun 25 2019
CROSSREFS
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved