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A093379 Expansion of x(1-2x-2x^2)/((1+x)(1-2x)(1-3x)). 1

%I

%S 0,1,2,5,12,31,82,225,632,1811,5262,15445,45652,135591,404042,1206665,

%T 3609072,10805371,32372422,97029885,290914892,872395151,2616486402,

%U 7848061105,23541387112,70618568931,211844521982,635511196325

%N Expansion of x(1-2x-2x^2)/((1+x)(1-2x)(1-3x)).

%C Binomial transform is A085280, with leading zero.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-1,-6).

%F a(n)=3^n/12-(-1)^n/12+2^n/3-0^n/3;

%F a(n)=4a(n-1)-a(n-2)-6a(n-3).

%F a(n)=A015518(n)/3+A000079(n)/3-0^n/3.

%t CoefficientList[Series[x (1-2x-2x^2)/((1+x)(1-2x)(1-3x)),{x,0,30}],x] (* or *) LinearRecurrence[{4,-1,-6},{0,1,2,5},40] (* _Harvey P. Dale_, May 10 2019 *)

%Y Cf. A087432.

%K easy,nonn

%O 0,3

%A _Paul Barry_, Apr 28 2004

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Last modified August 14 01:00 EDT 2020. Contains 336473 sequences. (Running on oeis4.)