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UnsplittableFactorCount on SetPartition ​

The number of unsplittable factors of the set partition under the split product.

On SetPartition

FindStat's St000823. The split product of set partitions of m and n glues the i-th block of the first to the i-th block of the second, shifted by m.

Called as CombinatorialStat(x, "UnsplittableFactorCount"). The head's page has its examples.

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Distribution

Over SetPartitions at each size, tallied here in your browser; sizes past 10 are not offered.

FindStat St000823

The number of unsplittable factors of the set partition.

ObjectValue
{{1,2}}2
{{1,2,3}}3
{{1},{2}}1
{{1,2,3,4}}4
{{1,2},{3}}2
{{1,3},{2}}2
{{1},{2,3}}1
{{1,2,3,4,5}}5

Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St000823 has the rest.