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Identifier
Values
=>
Cc0002;cc-rep
[2]=>0 [1,1]=>1 [3]=>0 [2,1]=>2 [1,1,1]=>3 [4]=>0 [3,1]=>3 [2,2]=>4 [2,1,1]=>5 [1,1,1,1]=>6 [5]=>0 [4,1]=>4 [3,2]=>6 [3,1,1]=>7 [2,2,1]=>8 [2,1,1,1]=>9 [1,1,1,1,1]=>10 [6]=>0 [5,1]=>5 [4,2]=>8 [4,1,1]=>9 [3,3]=>9 [3,2,1]=>11 [3,1,1,1]=>12 [2,2,2]=>12 [2,2,1,1]=>13 [2,1,1,1,1]=>14 [1,1,1,1,1,1]=>15 [7]=>0 [6,1]=>6 [5,2]=>10 [5,1,1]=>11 [4,3]=>12 [4,2,1]=>14 [4,1,1,1]=>15 [3,3,1]=>15 [3,2,2]=>16 [3,2,1,1]=>17 [3,1,1,1,1]=>18 [2,2,2,1]=>18 [2,2,1,1,1]=>19 [2,1,1,1,1,1]=>20 [1,1,1,1,1,1,1]=>21 [8]=>0 [7,1]=>7 [6,2]=>12 [6,1,1]=>13 [5,3]=>15 [5,2,1]=>17 [5,1,1,1]=>18 [4,4]=>16 [4,3,1]=>19 [4,2,2]=>20 [4,2,1,1]=>21 [4,1,1,1,1]=>22 [3,3,2]=>21 [3,3,1,1]=>22 [3,2,2,1]=>23 [3,2,1,1,1]=>24 [3,1,1,1,1,1]=>25 [2,2,2,2]=>24 [2,2,2,1,1]=>25 [2,2,1,1,1,1]=>26 [2,1,1,1,1,1,1]=>27 [1,1,1,1,1,1,1,1]=>28 [9]=>0 [8,1]=>8 [7,2]=>14 [7,1,1]=>15 [6,3]=>18 [6,2,1]=>20 [6,1,1,1]=>21 [5,4]=>20 [5,3,1]=>23 [5,2,2]=>24 [5,2,1,1]=>25 [5,1,1,1,1]=>26 [4,4,1]=>24 [4,3,2]=>26 [4,3,1,1]=>27 [4,2,2,1]=>28 [4,2,1,1,1]=>29 [4,1,1,1,1,1]=>30 [3,3,3]=>27 [3,3,2,1]=>29 [3,3,1,1,1]=>30 [3,2,2,2]=>30 [3,2,2,1,1]=>31 [3,2,1,1,1,1]=>32 [3,1,1,1,1,1,1]=>33 [2,2,2,2,1]=>32 [2,2,2,1,1,1]=>33 [2,2,1,1,1,1,1]=>34 [2,1,1,1,1,1,1,1]=>35 [1,1,1,1,1,1,1,1,1]=>36 [10]=>0 [9,1]=>9 [8,2]=>16 [8,1,1]=>17 [7,3]=>21 [7,2,1]=>23 [7,1,1,1]=>24 [6,4]=>24 [6,3,1]=>27 [6,2,2]=>28 [6,2,1,1]=>29 [6,1,1,1,1]=>30 [5,5]=>25 [5,4,1]=>29 [5,3,2]=>31 [5,3,1,1]=>32 [5,2,2,1]=>33 [5,2,1,1,1]=>34 [5,1,1,1,1,1]=>35 [4,4,2]=>32 [4,4,1,1]=>33 [4,3,3]=>33 [4,3,2,1]=>35 [4,3,1,1,1]=>36 [4,2,2,2]=>36 [4,2,2,1,1]=>37 [4,2,1,1,1,1]=>38 [4,1,1,1,1,1,1]=>39 [3,3,3,1]=>36 [3,3,2,2]=>37 [3,3,2,1,1]=>38 [3,3,1,1,1,1]=>39 [3,2,2,2,1]=>39 [3,2,2,1,1,1]=>40 [3,2,1,1,1,1,1]=>41 [3,1,1,1,1,1,1,1]=>42 [2,2,2,2,2]=>40 [2,2,2,2,1,1]=>41 [2,2,2,1,1,1,1]=>42 [2,2,1,1,1,1,1,1]=>43 [2,1,1,1,1,1,1,1,1]=>44 [1,1,1,1,1,1,1,1,1,1]=>45 [11]=>0 [10,1]=>10 [9,2]=>18 [9,1,1]=>19 [8,3]=>24 [8,2,1]=>26 [8,1,1,1]=>27 [7,4]=>28 [7,3,1]=>31 [7,2,2]=>32 [7,2,1,1]=>33 [7,1,1,1,1]=>34 [6,5]=>30 [6,4,1]=>34 [6,3,2]=>36 [6,3,1,1]=>37 [6,2,2,1]=>38 [6,2,1,1,1]=>39 [6,1,1,1,1,1]=>40 [5,5,1]=>35 [5,4,2]=>38 [5,4,1,1]=>39 [5,3,3]=>39 [5,3,2,1]=>41 [5,3,1,1,1]=>42 [5,2,2,2]=>42 [5,2,2,1,1]=>43 [5,2,1,1,1,1]=>44 [5,1,1,1,1,1,1]=>45 [4,4,3]=>40 [4,4,2,1]=>42 [4,4,1,1,1]=>43 [4,3,3,1]=>43 [4,3,2,2]=>44 [4,3,2,1,1]=>45 [4,3,1,1,1,1]=>46 [4,2,2,2,1]=>46 [4,2,2,1,1,1]=>47 [4,2,1,1,1,1,1]=>48 [4,1,1,1,1,1,1,1]=>49 [3,3,3,2]=>45 [3,3,3,1,1]=>46 [3,3,2,2,1]=>47 [3,3,2,1,1,1]=>48 [3,3,1,1,1,1,1]=>49 [3,2,2,2,2]=>48 [3,2,2,2,1,1]=>49 [3,2,2,1,1,1,1]=>50 [3,2,1,1,1,1,1,1]=>51 [3,1,1,1,1,1,1,1,1]=>52 [2,2,2,2,2,1]=>50 [2,2,2,2,1,1,1]=>51 [2,2,2,1,1,1,1,1]=>52 [2,2,1,1,1,1,1,1,1]=>53 [2,1,1,1,1,1,1,1,1,1]=>54 [1,1,1,1,1,1,1,1,1,1,1]=>55 [12]=>0 [11,1]=>11 [10,2]=>20 [10,1,1]=>21 [9,3]=>27 [9,2,1]=>29 [9,1,1,1]=>30 [8,4]=>32 [8,3,1]=>35 [8,2,2]=>36 [8,2,1,1]=>37 [8,1,1,1,1]=>38 [7,5]=>35 [7,4,1]=>39 [7,3,2]=>41 [7,3,1,1]=>42 [7,2,2,1]=>43 [7,2,1,1,1]=>44 [7,1,1,1,1,1]=>45 [6,6]=>36 [6,5,1]=>41 [6,4,2]=>44 [6,4,1,1]=>45 [6,3,3]=>45 [6,3,2,1]=>47 [6,3,1,1,1]=>48 [6,2,2,2]=>48 [6,2,2,1,1]=>49 [6,2,1,1,1,1]=>50 [6,1,1,1,1,1,1]=>51 [5,5,2]=>45 [5,5,1,1]=>46 [5,4,3]=>47 [5,4,2,1]=>49 [5,4,1,1,1]=>50 [5,3,3,1]=>50 [5,3,2,2]=>51 [5,3,2,1,1]=>52 [5,3,1,1,1,1]=>53 [5,2,2,2,1]=>53 [5,2,2,1,1,1]=>54 [5,2,1,1,1,1,1]=>55 [5,1,1,1,1,1,1,1]=>56 [4,4,4]=>48 [4,4,3,1]=>51 [4,4,2,2]=>52 [4,4,2,1,1]=>53 [4,4,1,1,1,1]=>54 [4,3,3,2]=>53 [4,3,3,1,1]=>54 [4,3,2,2,1]=>55 [4,3,2,1,1,1]=>56 [4,3,1,1,1,1,1]=>57 [4,2,2,2,2]=>56 [4,2,2,2,1,1]=>57 [4,2,2,1,1,1,1]=>58 [4,2,1,1,1,1,1,1]=>59 [4,1,1,1,1,1,1,1,1]=>60 [3,3,3,3]=>54 [3,3,3,2,1]=>56 [3,3,3,1,1,1]=>57 [3,3,2,2,2]=>57 [3,3,2,2,1,1]=>58 [3,3,2,1,1,1,1]=>59 [3,3,1,1,1,1,1,1]=>60 [3,2,2,2,2,1]=>59 [3,2,2,2,1,1,1]=>60 [3,2,2,1,1,1,1,1]=>61 [3,2,1,1,1,1,1,1,1]=>62 [3,1,1,1,1,1,1,1,1,1]=>63 [2,2,2,2,2,2]=>60 [2,2,2,2,2,1,1]=>61 [2,2,2,2,1,1,1,1]=>62 [2,2,2,1,1,1,1,1,1]=>63 [2,2,1,1,1,1,1,1,1,1]=>64 [2,1,1,1,1,1,1,1,1,1,1]=>65 [1,1,1,1,1,1,1,1,1,1,1,1]=>66
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Description
The sum of the products of all pairs of parts.
This is the evaluation of the second elementary symmetric polynomial which is equal to
$$e_2(\lambda) = \binom{n+1}{2} - \sum_{i=1}^\ell\binom{\lambda_i+1}{2}$$
for a partition $\lambda = (\lambda_1,\dots,\lambda_\ell) \vdash n$, see [1].
This is the maximal number of inversions a permutation with the given shape can have, see [2, cor.2.4].
References
[1] Kopitzke, G. The Gini Index of an Integer Partition arXiv:2005.04284
[2] Hohlweg, C. Minimal and maximal elements in Kazhdan-Lusztig double sided cells of $S_n$ and Robinson-Schensted correspondance arXiv:math/0304059
Code
def statistic(L):
    return sum(L[a]*L[b] for a,b in Subsets(range(len(L)), 2))

def statistic_alt(L):
    n = sum(L)
    return binomial(n+1,2) - sum(binomial(l+1,2) for l in L)
Created
Aug 07, 2016 at 13:18 by Martin Rubey
Updated
Nov 09, 2021 at 15:38 by Martin Rubey