OFFSET
0,5
LINKS
EXAMPLE
The a(8) = 6 set partitions:
{{1,2,3,4,5,6,7,8}}
{{1,2,7,8},{3,4,5,6}}
{{1,3,6,8},{2,4,5,7}}
{{1,4,5,8},{2,3,6,7}}
{{1,4,6,7},{2,3,5,8}}
{{1,8},{2,7},{3,6},{4,5}}
MATHEMATICA
sps[{}]:={{}}; sps[set:{i_, ___}]:=Join@@Function[s, Prepend[#, s]&/@sps[Complement[set, s]]]/@Cases[Subsets[set], {i, ___}];
Table[Length[Select[sps[Range[n]], And[SameQ@@Length/@#, SameQ@@Total/@#]&]], {n, 0, 8}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Sep 29 2019
STATUS
approved