DoubleDescents on Permutation
Positions i with p(i) > p(i+1) > p(i+2).
Called as CombinatorialStat(x, "DoubleDescents"). The head's page has its examples.
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FindStat St000366
The number of double descents of a permutation.
| Object | Value |
|---|---|
[] | 0 |
[1] | 0 |
[1,2] | 0 |
[2,1] | 0 |
[1,2,3] | 0 |
[1,3,2] | 0 |
[2,1,3] | 0 |
[2,3,1] | 0 |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St000366 has the rest.