|
%I #16 Apr 18 2017 07:04:09
%S 0,2,3,9,41,252,1954,18302,200906,2528152,35862456,565985472,
%T 9834073248,186504365616,3833188731072,84862243895088,
%U 2013237501351504,50950031663224320,1370088133344414336,39011485705595544960,1172540863138831491456,37097659139410654988544
%N A simple grammar: union of cycles and cycles of cycles.
%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=793">Encyclopedia of Combinatorial Structures 793</a>
%F E.g.f.: log(-1/(-1+x))+log(-1/(-1+log(-1/(-1+x)))).
%p spec := [S,{B=Cycle(C),C=Cycle(Z),S=Union(C,B)},labeled]: seq(combstruct[count](spec, size=n), n=0..20);
%K easy,nonn
%O 0,2
%A encyclopedia(AT)pommard.inria.fr, Jan 25 2000
%E More terms from _Alois P. Heinz_, Mar 16 2016
|
