%I A052890
%S A052890 1,1,2,6,16,49,153,493,1623,5460,18625,64373,224843,792546,2815443,
%T A052890 10070115,36233440,131063713,476320360,1738401482,6368750019
%N A052890 A simple grammar.
%H A052890 INRIA Algorithms Project, <a href="http://algo.inria.fr/bin/encyclopedia?Search=ECSnb&argsearch=866">
               Encyclopedia of Combinatorial Structures 866</a>
%p A052890 spec := [S,{B=Set(C,1 <= card),C=Prod(Z,S),S=PowerSet(B)},unlabeled]: 
               seq(combstruct[count](spec,size=n), n=0..20);
%Y A052890 Sequence in context: A151528 A132803 A079565 this_sequence A052814 A151445 
               A000136
%Y A052890 Adjacent sequences: A052887 A052888 A052889 this_sequence A052891 A052892 
               A052893
%K A052890 easy,nonn
%O A052890 0,3
%A A052890 encyclopedia(AT)pommard.inria.fr, Jan 25 2000