%I A052732
%S A052732 0,0,0,0,24,240,3600,70560,1693440,47900160,1556755200,57081024000,
%T A052732 2328905779200,104589041356800,5124863026483200,272011960636416000,
%U A052732 15543540607795200000,951264685197066240000,62070020709108572160000
%N A052732 A simple context-free grammar in a labeled universe.
%H A052732 INRIA Algorithms Project, <a href="http://algo.inria.fr/bin/encyclopedia?Search=ECSnb&argsearch=688">
               Encyclopedia of Combinatorial Structures 688</a>
%F A052732 E.g.f.: (1/2-x-1/2*(1-4*x)^(1/2))*x^2
%F A052732 Recurrence: {a(1)=0, a(2)=0, a(3)=0, a(4)=24, (-4*n^2+6*n+10)*a(n)+(n-1)*a(n+1), 
               a(5)=240}
%F A052732 {a(1)=0, a(n+5)=0}
%p A052732 spec := [S,{B=Union(Z,C),C=Prod(B,B),S=Prod(Z,Z,C)},labeled]: seq(combstruct[count](spec,
               size=n), n=0..20);
%Y A052732 Sequence in context: A000536 A151720 A052652 this_sequence A086603 A000594 
               A022716
%Y A052732 Adjacent sequences: A052729 A052730 A052731 this_sequence A052733 A052734 
               A052735
%K A052732 easy,nonn
%O A052732 0,5
%A A052732 encyclopedia(AT)pommard.inria.fr, Jan 25 2000