OFFSET
0,3
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..999
Index entries for linear recurrences with constant coefficients, signature (1, 2, 2).
FORMULA
a(0)=1, a(1)=0, a(2)=2, a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3). - Harvey P. Dale, Sep 25 2011
MATHEMATICA
CoefficientList[Series[(1-x)/(1-x-2x^2-2x^3), {x, 0, 40}], x] (* or *) LinearRecurrence[{1, 2, 2}, {1, 0, 2}, 41] (* Harvey P. Dale, Sep 25 2011 *)
PROG
(PARI) Vec((1-x)/(1-x-2*x^2-2*x^3)+O(x^40)) \\ Charles R Greathouse IV, Sep 27 2012
(Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1-x)/(1-x-2*x^2-2*x^3) )); // G. C. Greubel, Jun 27 2019
(Sage) ((1-x)/(1-x-2*x^2-2*x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Jun 27 2019
(GAP) a:=[1, 0, 2];; for n in [4..40] do a[n]:=a[n-1]+2*a[n-2]+2*a[n-3]; od; a; # G. C. Greubel, Jun 27 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved