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Coefficient of x in the reduction by (x^3 -> x + 1) of the polynomial F(n+1)*x^n, where F(n)=A000045 (Fibonacci sequence).
2

%I #19 Sep 08 2022 08:45:58

%S 0,1,0,3,10,24,78,231,680,2035,6052,18000,53590,159471,474580,1412397,

%T 4203304,12509144,37227624,110790405,329715412,981242533,2920205614,

%U 8690615136,25863518300,76970566973,229066599960,681708726543

%N Coefficient of x in the reduction by (x^3 -> x + 1) of the polynomial F(n+1)*x^n, where F(n)=A000045 (Fibonacci sequence).

%C See A192911.

%H G. C. Greubel, <a href="/A192912/b192912.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (1,4,5,2,-1,1).

%F (See A192911.)

%F G.f.: x*(1-x-x^2+2*x^3)/(1-x-4*x^2-5*x^3-2*x^4+x^5-x^6). - _R. J. Mathar_, May 08 2014

%e (See A192911.)

%t (See A192911.)

%t LinearRecurrence[{1,4,5,2,-1,1},{0,1,0,3,10,24},28] (* _Ray Chandler_, Aug 02 2015 *)

%o (PARI) my(x='x+O('x^30)); concat([0], Vec(x*(1-x-x^2+2*x^3)/(1-x-4*x^2 -5*x^3-2*x^4+x^5-x^6))) \\ _G. C. Greubel_, Jan 12 2019

%o (Magma) m:=30; R<x>:=PowerSeriesRing(Integers(), m); [0] cat Coefficients(R!( x*(1-x-x^2+2*x^3)/(1-x-4*x^2-5*x^3-2*x^4+x^5-x^6) )); // _G. C. Greubel_, Jan 12 2019

%o (Sage) (x*(1-x-x^2+2*x^3)/(1-x-4*x^2-5*x^3-2*x^4+x^5-x^6)).series(x, 30).coefficients(x, sparse=False) # _G. C. Greubel_, Jan 12 2019

%o (GAP) a:=[0,1,0,3,10,24];; for n in [7..30] do a[n]:=a[n-1]+4*a[n-2]+ 5*a[n-3]+2*a[n-4]-a[n-5]+a[n-6]; od; a; # _G. C. Greubel_, Jan 12 2019

%Y Cf. A192232, A192744, A192911.

%K nonn

%O 0,4

%A _Clark Kimberling_, Jul 12 2011