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%I #4 Jun 17 2023 07:46:40
%S 0,1,1,1,3,6,10,18,34,63,115,211,389,716,1316,2420,4452,8189,15061,
%T 27701,50951,93714,172366,317030,583110,1072507,1972647,3628263,
%U 6673417,12274328,22576008,41523752,76374088,140473849,258371689
%N a(n)=Sum((-1)^(i+Floor(n/2))T(2i+e),(i=0,..,Floor(n/2))), where T(n) are tribonacci numbers (A000073) and e=(1/2)(1-(-1)^n).
%C a(n) is the convolution of T(n) with the sequence (1,0,-1,0,1,0,-1,0,....) A056594.
%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, 2, 1, 1).
%F a(n)=a(n-1)+2a(n-3)+a(n-4)+a(n-5), a(0)=0, a(1)=1, a(2)=1, a(3)=1, a(4)=3. G.f.: x/(1 - x - 2*x^3 - x^4 - x^5).
%t CoefficientList[Series[x/(1 - x - 2*x^3 - x^4 - x^5), {x, 0, 40}], x]
%Y Cf. A000073, A056594, A074662, A074677, A074678.
%K easy,nonn
%O 0,5
%A Mario Catalani (mario.catalani(AT)unito.it), Sep 01 2002
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