DescentsPlusRecoils on Permutation

Descents plus recoils: the two counts added, not the union of the indices.

On Permutation

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

Live

Distribution

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Sizes 1 to

FindStat St000824

The sum of the number of descents and the number of recoils of a permutation.

Object	Value
[1,2]	0
[2,1]	2
[1,2,3]	0
[1,3,2]	2
[2,1,3]	2
[2,3,1]	2
[3,1,2]	2
[3,2,1]	4

Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St000824 has the rest.