OFFSET
1,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (-1,1,1,1,0,-1).
FORMULA
G.f.: -x - x^3*(2 -2*x^4 +x^5)/((1-x^2)*(1+x+x^4)).
MATHEMATICA
Rest@CoefficientList[Series[-x -x^3*(2-2*x^4+x^5)/((1-x^2)*(1+x-x^4)), {x, 0, 50}], x] (* G. C. Greubel, Feb 19 2021 *)
LinearRecurrence[{-1, 1, 1, 1, 0, -1}, {-1, 0, -2, 2, -4, 4, -6, 7}, 50] (* Harvey P. Dale, Aug 11 2021 *)
PROG
(Sage)
def A089076_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( -x -x^3*(2-2*x^4+x^5)/((1-x^2)*(1+x-x^4)) ).list()
a=A089076_list(51); a[1:] # G. C. Greubel, Feb 19 2021
(Magma)
R<x>:=PowerSeriesRing(Integers(), 50);
Coefficients(R!( -x -x^3*(2-2*x^4+x^5)/((1-x^2)*(1+x-x^4)) )); // G. C. Greubel, Feb 19 2021
CROSSREFS
KEYWORD
sign
AUTHOR
Roger L. Bagula, Dec 04 2003
EXTENSIONS
Edited by G. C. Greubel, Feb 19 2021
STATUS
approved