%I A052822
%S A052822 0,0,2,12,80,630,5816,61978,751222,10225140,154610048,2573280820,
%T A052822 46775427860,922374085984,19616567407368,447666534959528,
%U A052822 10913339500879576,283081184691349600,7785415448640271232
%N A052822 A simple grammar: pairs of cycles of cycles.
%H A052822 INRIA Algorithms Project, <a href="http://algo.inria.fr/bin/encyclopedia?Search=ECSnb&argsearch=787">
               Encyclopedia of Combinatorial Structures 787</a>
%F A052822 E.g.f.: ln(-1/(-1+ln(-1/(-1+x))))^2
%p A052822 pairs spec := [S,{B=Cycle(Z),C=Cycle(B),S=Prod(C,C)},labeled]: seq(combstruct[count](spec,
               size=n), n=0..20);
%Y A052822 Sequence in context: A082142 A069723 A063481 this_sequence A058872 A055548 
               A092850
%Y A052822 Adjacent sequences: A052819 A052820 A052821 this_sequence A052823 A052824 
               A052825
%K A052822 easy,nonn
%O A052822 0,3
%A A052822 encyclopedia(AT)pommard.inria.fr, Jan 25 2000