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DoubleDeficiencies on Permutation ​

Positions with i > p(i) > p(p(i)).

On Permutation

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

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Distribution

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FindStat St000732

The number of double deficiencies of a permutation.

The number of double deficiencies of a permutation. A double deficiency is an index σ(i)\sigma(i) such that i>σ(i)>σ(σ(i))i > \sigma(i) > \sigma(\sigma(i)).
ObjectValue
[1,2]0
[2,1]0
[1,2,3]0
[1,3,2]0
[2,1,3]0
[2,3,1]0
[3,1,2]1
[3,2,1]0

Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St000732 has the rest.