OFFSET
0,4
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
E. Kirkman, J. Kuzmanovich and J. J. Zhang, Invariants of (-1)-Skew Polynomial Rings under Permutation Representations, arXiv preprint arXiv:1305.3973, 2013
FORMULA
G.f.: (1-x+x^2)*(1-2 *x+2*x^2-x^3+2*x^4-2*x^5+x^6)/((1+x^2)^2*(1-x)^4*(1+x^4)).
MATHEMATICA
CoefficientList[Series[(1 - 3 x + 5 x^2 - 5 x^3 + 5 x^4 - 5 x^5 + 5 x^6 - 3 x^7 + x^8) / ((1 - x)^4 (1 + x^4) (1 + x^2)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Sep 07 2013 *)
PROG
(Magma) m:=50; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-3*x+5*x^2-5*x^3+5*x^4-5*x^5+5*x^6-3*x^7+x^8)/((1-x)^4*(1+x^4)*(1+x^2)^2))); // Vincenzo Librandi, Sep 07 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Sep 06 2013
STATUS
approved