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A326513 Number of set partitions of {1..n} where each block has a different average. 16
1, 1, 2, 4, 12, 40, 154, 650, 3024, 15110, 81538, 468494, 2863340 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
EXAMPLE
The a(1) = 1 through a(4) = 12 set partitions:
{{1}} {{1,2}} {{1,2,3}} {{1,2,3,4}}
{{1},{2}} {{1},{2,3}} {{1},{2,3,4}}
{{1,2},{3}} {{1,2},{3,4}}
{{1},{2},{3}} {{1,2,3},{4}}
{{1,2,4},{3}}
{{1,3},{2,4}}
{{1,3,4},{2}}
{{1},{2},{3,4}}
{{1},{2,3},{4}}
{{1,2},{3},{4}}
{{1,4},{2},{3}}
{{1},{2},{3},{4}}
MATHEMATICA
sps[{}]:={{}}; sps[set:{i_, ___}]:=Join@@Function[s, Prepend[#, s]&/@sps[Complement[set, s]]]/@Cases[Subsets[set], {i, ___}];
Table[Length[Select[sps[Range[n]], UnsameQ@@Mean/@#&]], {n, 0, 8}]
CROSSREFS
Sequence in context: A074034 A268952 A215072 * A268953 A268954 A268955
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jul 11 2019
EXTENSIONS
a(12) from Alois P. Heinz, Jul 12 2019
STATUS
approved

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Last modified February 25 13:12 EST 2024. Contains 370330 sequences. (Running on oeis4.)