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A052605 Expansion of E.g.f. x*(1-x)/(1-x-x^3). 0

%I

%S 0,1,0,0,24,120,720,10080,120960,1451520,21772800,359251200,

%T 6227020800,118313395200,2440992153600,53614649088000,

%U 1255367393280000,31300493672448000,825906208038912000

%N Expansion of E.g.f. x*(1-x)/(1-x-x^3).

%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=550">Encyclopedia of Combinatorial Structures 550</a>

%F E.g.f.: x*(-1+x)/(-1+x+x^3).

%F Recurrence: a(1)=1, a(0)=0, a(2)=0, (-11*n-6-n^3-6*n^2)*a(n) +(-n-3)*a(n+2) +a(n+3) = 0.

%F Sum(1/31*(_alpha+11*_alpha^2-3)*_alpha^(-1-n), _alpha=RootOf(-1+_Z+_Z^3))*n!.

%p spec := [S,{S=Prod(Z,Sequence(Prod(Z,Z,Z,Sequence(Z))))},labeled]: seq(combstruct[count](spec,size=n), n=0..20);

%K easy,nonn

%O 0,5

%A encyclopedia(AT)pommard.inria.fr, Jan 25 2000

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Last modified June 22 04:06 EDT 2021. Contains 345367 sequences. (Running on oeis4.)