OFFSET
1,2
EXAMPLE
The a(3)=8 shuffles are:
(111)<=((111)), (111)<=((1)(11)), (111)<=((1)(1)(1)),
(12)<=((12)), (12)<=((1)(2)),
(21)<=((21)), (21)<=((1)(2)),
(3)<=((3)).
MATHEMATICA
nn=10;
comps[0]:={{}}; comps[n_]:=Join@@Table[Prepend[#, i]&/@comps[n-i], {i, n}];
sps[{}]:={{}}; sps[set:{i_, ___}]:=Join@@Function[s, Prepend[#, s]&/@sps[Complement[set, s]]]/@Cases[Subsets[set], {i, ___}];
dealings[q_]:=Union[Function[ptn, Sort[q[[#]]&/@ptn]]/@sps[Range[Length[q]]]];
Table[Total[Length/@dealings/@comps[n]], {n, nn}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Sep 26 2017
EXTENSIONS
a(12) from Robert Price, Sep 16 2018
STATUS
approved