OFFSET
0,4
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1, -1, -1).
FORMULA
G.f.: (1-x)/(1-x+x^2+x^3).
a(0)=1, a(1)=0, a(2)=-1, a(n) = a(n-1) - a(n-2) - a(n-3). - Harvey P. Dale, Nov 08 2011
MATHEMATICA
CoefficientList[Series[(1-x)/(1-x+x^2+x^3), {x, 0, 50}], x] (* or *) LinearRecurrence[ {1, -1, -1}, {1, 0, -1}, 50] (* Harvey P. Dale, Nov 08 2011 *)
PROG
(PARI) my(x='x+O('x^50)); Vec((1-x)/(1-x+x^2+x^3)) \\ G. C. Greubel, Jun 29 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( (1-x)/(1-x+x^2+x^3) )); // G. C. Greubel, Jun 29 2019
(Sage) ((1-x)/(1-x+x^2+x^3)).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Jun 29 2019
(GAP) a:=[1, 0, -1];; for n in [4..50] do a[n]:=a[n-1]-a[n-2]-a[n-3]; od; a; # G. C. Greubel, Jun 29 2019
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved