OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (9,-32,63,-84,81,-56,27,-8,1).
FORMULA
G.f.: (1 +x^2)^7/(1 -9*x +32*x^2 -63*x^3 +84*x^4 -81*x^5 +56*x^6 -27*x^7 +8*x^8 -x^9).
MATHEMATICA
CoefficientList[Series[(1+x^2)^7/(1-9*x+32*x^2-63*x^3+84*x^4-81*x^5+56*x^6-27*x^7+8*x^8-x^9), {x, 0, 50}], x] (* G. C. Greubel, Apr 20 2021 *)
PROG
(Magma)
R<x>:=PowerSeriesRing(Integers(), 50);
Coefficients(R!( (1+x^2)^7/(1-9*x+32*x^2-63*x^3+84*x^4-81*x^5+56*x^6-27*x^7+8*x^8-x^9) )); // G. C. Greubel, Apr 20 2021
(Sage)
def A097556_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( (1+x^2)^7/(1-9*x+32*x^2-63*x^3+84*x^4-81*x^5+56*x^6-27*x^7+8*x^8-x^9) ).list()
A097556_list(50) # G. C. Greubel, Apr 20 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
D n Verma, Aug 16 2004
EXTENSIONS
Edited and extended by Max Alekseyev, Jun 17 2011
STATUS
approved