*****************************************************************************
*       www.FindStat.org - The Combinatorial Statistic Finder               *
*                                                                           *
*       Copyright (C) 2019 The FindStatCrew <info@findstat.org>             *
*                                                                           *
*    This information is distributed in the hope that it will be useful,    *
*    but WITHOUT ANY WARRANTY; without even the implied warranty of         *
*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                   *
*****************************************************************************

-----------------------------------------------------------------------------
Statistic identifier: St000008

-----------------------------------------------------------------------------
Collection: Integer compositions

-----------------------------------------------------------------------------
Description: The major index of the composition.

The descents of a composition $[c_1,c_2,\dots,c_k]$ are the partial sums $c_1, c_1+c_2,\dots, c_1+\dots+c_{k-1}$, excluding the sum of all parts.  The major index of a composition is the sum of its descents.

For details about the major index see [[Permutations/Descents-Major]].

-----------------------------------------------------------------------------
References: 

-----------------------------------------------------------------------------
Code:
def statistic(x):
    return x.major_index()

-----------------------------------------------------------------------------
Statistic values:

[1]                       => 0
[1,1]                     => 1
[2]                       => 0
[1,1,1]                   => 3
[1,2]                     => 1
[2,1]                     => 2
[3]                       => 0
[1,1,1,1]                 => 6
[1,1,2]                   => 3
[1,2,1]                   => 4
[1,3]                     => 1
[2,1,1]                   => 5
[2,2]                     => 2
[3,1]                     => 3
[4]                       => 0
[1,1,1,1,1]               => 10
[1,1,1,2]                 => 6
[1,1,2,1]                 => 7
[1,1,3]                   => 3
[1,2,1,1]                 => 8
[1,2,2]                   => 4
[1,3,1]                   => 5
[1,4]                     => 1
[2,1,1,1]                 => 9
[2,1,2]                   => 5
[2,2,1]                   => 6
[2,3]                     => 2
[3,1,1]                   => 7
[3,2]                     => 3
[4,1]                     => 4
[5]                       => 0
[1,1,1,1,1,1]             => 15
[1,1,1,1,2]               => 10
[1,1,1,2,1]               => 11
[1,1,1,3]                 => 6
[1,1,2,1,1]               => 12
[1,1,2,2]                 => 7
[1,1,3,1]                 => 8
[1,1,4]                   => 3
[1,2,1,1,1]               => 13
[1,2,1,2]                 => 8
[1,2,2,1]                 => 9
[1,2,3]                   => 4
[1,3,1,1]                 => 10
[1,3,2]                   => 5
[1,4,1]                   => 6
[1,5]                     => 1
[2,1,1,1,1]               => 14
[2,1,1,2]                 => 9
[2,1,2,1]                 => 10
[2,1,3]                   => 5
[2,2,1,1]                 => 11
[2,2,2]                   => 6
[2,3,1]                   => 7
[2,4]                     => 2
[3,1,1,1]                 => 12
[3,1,2]                   => 7
[3,2,1]                   => 8
[3,3]                     => 3
[4,1,1]                   => 9
[4,2]                     => 4
[5,1]                     => 5
[6]                       => 0
[1,1,1,1,1,1,1]           => 21
[1,1,1,1,1,2]             => 15
[1,1,1,1,2,1]             => 16
[1,1,1,1,3]               => 10
[1,1,1,2,1,1]             => 17
[1,1,1,2,2]               => 11
[1,1,1,3,1]               => 12
[1,1,1,4]                 => 6
[1,1,2,1,1,1]             => 18
[1,1,2,1,2]               => 12
[1,1,2,2,1]               => 13
[1,1,2,3]                 => 7
[1,1,3,1,1]               => 14
[1,1,3,2]                 => 8
[1,1,4,1]                 => 9
[1,1,5]                   => 3
[1,2,1,1,1,1]             => 19
[1,2,1,1,2]               => 13
[1,2,1,2,1]               => 14
[1,2,1,3]                 => 8
[1,2,2,1,1]               => 15
[1,2,2,2]                 => 9
[1,2,3,1]                 => 10
[1,2,4]                   => 4
[1,3,1,1,1]               => 16
[1,3,1,2]                 => 10
[1,3,2,1]                 => 11
[1,3,3]                   => 5
[1,4,1,1]                 => 12
[1,4,2]                   => 6
[1,5,1]                   => 7
[1,6]                     => 1
[2,1,1,1,1,1]             => 20
[2,1,1,1,2]               => 14
[2,1,1,2,1]               => 15
[2,1,1,3]                 => 9
[2,1,2,1,1]               => 16
[2,1,2,2]                 => 10
[2,1,3,1]                 => 11
[2,1,4]                   => 5
[2,2,1,1,1]               => 17
[2,2,1,2]                 => 11
[2,2,2,1]                 => 12
[2,2,3]                   => 6
[2,3,1,1]                 => 13
[2,3,2]                   => 7
[2,4,1]                   => 8
[2,5]                     => 2
[3,1,1,1,1]               => 18
[3,1,1,2]                 => 12
[3,1,2,1]                 => 13
[3,1,3]                   => 7
[3,2,1,1]                 => 14
[3,2,2]                   => 8
[3,3,1]                   => 9
[3,4]                     => 3
[4,1,1,1]                 => 15
[4,1,2]                   => 9
[4,2,1]                   => 10
[4,3]                     => 4
[5,1,1]                   => 11
[5,2]                     => 5
[6,1]                     => 6
[7]                       => 0
[1,1,1,1,1,1,1,1]         => 28
[1,1,1,1,1,1,2]           => 21
[1,1,1,1,1,2,1]           => 22
[1,1,1,1,1,3]             => 15
[1,1,1,1,2,1,1]           => 23
[1,1,1,1,2,2]             => 16
[1,1,1,1,3,1]             => 17
[1,1,1,1,4]               => 10
[1,1,1,2,1,1,1]           => 24
[1,1,1,2,1,2]             => 17
[1,1,1,2,2,1]             => 18
[1,1,1,2,3]               => 11
[1,1,1,3,1,1]             => 19
[1,1,1,3,2]               => 12
[1,1,1,4,1]               => 13
[1,1,1,5]                 => 6
[1,1,2,1,1,1,1]           => 25
[1,1,2,1,1,2]             => 18
[1,1,2,1,2,1]             => 19
[1,1,2,1,3]               => 12
[1,1,2,2,1,1]             => 20
[1,1,2,2,2]               => 13
[1,1,2,3,1]               => 14
[1,1,2,4]                 => 7
[1,1,3,1,1,1]             => 21
[1,1,3,1,2]               => 14
[1,1,3,2,1]               => 15
[1,1,3,3]                 => 8
[1,1,4,1,1]               => 16
[1,1,4,2]                 => 9
[1,1,5,1]                 => 10
[1,1,6]                   => 3
[1,2,1,1,1,1,1]           => 26
[1,2,1,1,1,2]             => 19
[1,2,1,1,2,1]             => 20
[1,2,1,1,3]               => 13
[1,2,1,2,1,1]             => 21
[1,2,1,2,2]               => 14
[1,2,1,3,1]               => 15
[1,2,1,4]                 => 8
[1,2,2,1,1,1]             => 22
[1,2,2,1,2]               => 15
[1,2,2,2,1]               => 16
[1,2,2,3]                 => 9
[1,2,3,1,1]               => 17
[1,2,3,2]                 => 10
[1,2,4,1]                 => 11
[1,2,5]                   => 4
[1,3,1,1,1,1]             => 23
[1,3,1,1,2]               => 16
[1,3,1,2,1]               => 17
[1,3,1,3]                 => 10
[1,3,2,1,1]               => 18
[1,3,2,2]                 => 11
[1,3,3,1]                 => 12
[1,3,4]                   => 5
[1,4,1,1,1]               => 19
[1,4,1,2]                 => 12
[1,4,2,1]                 => 13
[1,4,3]                   => 6
[1,5,1,1]                 => 14
[1,5,2]                   => 7
[1,6,1]                   => 8
[1,7]                     => 1
[2,1,1,1,1,1,1]           => 27
[2,1,1,1,1,2]             => 20
[2,1,1,1,2,1]             => 21
[2,1,1,1,3]               => 14
[2,1,1,2,1,1]             => 22
[2,1,1,2,2]               => 15
[2,1,1,3,1]               => 16
[2,1,1,4]                 => 9
[2,1,2,1,1,1]             => 23
[2,1,2,1,2]               => 16
[2,1,2,2,1]               => 17
[2,1,2,3]                 => 10
[2,1,3,1,1]               => 18
[2,1,3,2]                 => 11
[2,1,4,1]                 => 12
[2,1,5]                   => 5
[2,2,1,1,1,1]             => 24
[2,2,1,1,2]               => 17
[2,2,1,2,1]               => 18
[2,2,1,3]                 => 11
[2,2,2,1,1]               => 19
[2,2,2,2]                 => 12
[2,2,3,1]                 => 13
[2,2,4]                   => 6
[2,3,1,1,1]               => 20
[2,3,1,2]                 => 13
[2,3,2,1]                 => 14
[2,3,3]                   => 7
[2,4,1,1]                 => 15
[2,4,2]                   => 8
[2,5,1]                   => 9
[2,6]                     => 2
[3,1,1,1,1,1]             => 25
[3,1,1,1,2]               => 18
[3,1,1,2,1]               => 19
[3,1,1,3]                 => 12
[3,1,2,1,1]               => 20
[3,1,2,2]                 => 13
[3,1,3,1]                 => 14
[3,1,4]                   => 7
[3,2,1,1,1]               => 21
[3,2,1,2]                 => 14
[3,2,2,1]                 => 15
[3,2,3]                   => 8
[3,3,1,1]                 => 16
[3,3,2]                   => 9
[3,4,1]                   => 10
[3,5]                     => 3
[4,1,1,1,1]               => 22
[4,1,1,2]                 => 15
[4,1,2,1]                 => 16
[4,1,3]                   => 9
[4,2,1,1]                 => 17
[4,2,2]                   => 10
[4,3,1]                   => 11
[4,4]                     => 4
[5,1,1,1]                 => 18
[5,1,2]                   => 11
[5,2,1]                   => 12
[5,3]                     => 5
[6,1,1]                   => 13
[6,2]                     => 6
[7,1]                     => 7
[8]                       => 0
[1,1,1,1,4,1]             => 18
[1,1,1,2,3,1]             => 19
[1,1,2,1,3,1]             => 20
[1,1,6,1]                 => 11
[1,2,1,1,3,1]             => 21
[1,2,1,2,2,1]             => 22
[1,2,2,1,2,1]             => 23
[1,2,5,1]                 => 12
[1,3,1,1,2,1]             => 24
[1,3,1,2,1,1]             => 25
[1,3,2,1,1,1]             => 26
[1,3,4,1]                 => 13
[1,4,1,1,1,1]             => 27
[1,4,1,3]                 => 12
[1,4,2,2]                 => 13
[1,4,3,1]                 => 14
[1,5,1,2]                 => 14
[1,5,2,1]                 => 15
[1,6,1,1]                 => 16
[1,6,2]                   => 8
[1,7,1]                   => 9
[1,8]                     => 1
[2,1,5,1]                 => 13
[2,2,4,1]                 => 14
[3,1,4,1]                 => 15
[6,2,1]                   => 14
[7,1,1]                   => 15
[8,1]                     => 8
[1,1,1,1,1,1,1,1,1,1]     => 45
[1,1,1,1,1,1,2,2]         => 29
[1,1,1,1,2,1,1,2]         => 31
[1,1,1,1,2,2,1,1]         => 33
[1,1,1,1,3,3]             => 17
[1,1,1,1,5,1]             => 19
[1,1,2,1,1,1,1,2]         => 33
[1,1,2,1,1,2,1,1]         => 35
[1,1,2,1,2,3]             => 19
[1,1,2,2,1,1,1,1]         => 37
[1,1,2,2,2,2]             => 21
[1,1,3,1,1,3]             => 21
[1,1,3,2,1,2]             => 23
[1,1,3,3,1,1]             => 25
[1,1,4,4]                 => 9
[1,1,7,1]                 => 12
[1,2,1,1,4,1]             => 22
[1,2,6,1]                 => 13
[1,3,1,1,3,1]             => 25
[1,3,5,1]                 => 14
[1,4,1,1,2,1]             => 28
[1,4,4,1]                 => 15
[1,5,1,1,1,1]             => 31
[1,5,3,1]                 => 16
[1,6,1,2]                 => 16
[1,6,2,1]                 => 17
[1,7,1,1]                 => 18
[1,8,1]                   => 10
[1,9]                     => 1
[2,1,1,1,1,1,1,2]         => 35
[2,1,1,1,1,2,1,1]         => 37
[2,1,1,1,2,3]             => 21
[2,1,1,2,1,1,1,1]         => 39
[2,1,1,2,2,2]             => 23
[2,1,2,1,1,3]             => 23
[2,1,2,2,1,2]             => 25
[2,1,2,3,1,1]             => 27
[2,1,3,4]                 => 11
[2,1,6,1]                 => 14
[2,2,1,1,1,1,1,1]         => 41
[2,2,1,1,2,2]             => 25
[2,2,2,1,1,2]             => 27
[2,2,2,2,1,1]             => 29
[2,2,3,3]                 => 13
[3,1,1,1,1,3]             => 25
[3,1,1,2,1,2]             => 27
[3,1,1,3,1,1]             => 29
[3,1,2,4]                 => 13
[3,2,1,1,1,2]             => 29
[3,2,1,2,1,1]             => 31
[3,2,2,3]                 => 15
[3,3,1,1,1,1]             => 33
[3,3,2,2]                 => 17
[4,1,1,4]                 => 15
[4,2,1,3]                 => 17
[4,3,1,2]                 => 19
[4,4,1,1]                 => 21
[5,5]                     => 5
[8,1,1]                   => 17
[9,1]                     => 9
[1,10]                    => 1
[1,8,1,1]                 => 20
[1,7,2,1]                 => 19
[1,6,3,1]                 => 18
[1,5,4,1]                 => 17
[1,4,5,1]                 => 16
[1,3,6,1]                 => 15
[1,2,7,1]                 => 14
[1,1,8,1]                 => 13
[10,1]                    => 10
[1,1,1,1,1,1,1,1,1,1,1,1] => 66
[1,1,1,1,1,1,1,1,2,2]     => 46
[1,1,1,1,1,1,2,2,1,1]     => 50
[1,1,1,1,1,1,2,1,1,2]     => 48
[1,1,1,1,1,1,3,3]         => 30
[1,1,1,1,2,2,1,1,1,1]     => 54
[1,1,1,1,2,2,2,2]         => 34
[1,1,1,1,2,1,1,2,1,1]     => 52
[1,1,1,1,2,1,1,1,1,2]     => 50
[1,1,1,1,2,1,2,3]         => 32
[1,1,1,1,3,3,1,1]         => 38
[1,1,1,1,3,2,1,2]         => 36
[1,1,1,1,3,1,1,3]         => 34
[1,1,1,1,4,4]             => 18
[1,1,2,2,1,1,1,1,1,1]     => 58
[1,1,2,2,1,1,2,2]         => 38
[1,1,2,2,2,2,1,1]         => 42
[1,1,2,2,2,1,1,2]         => 40
[1,1,2,2,3,3]             => 22
[1,1,2,1,1,2,1,1,1,1]     => 56
[1,1,2,1,1,2,2,2]         => 36
[1,1,2,1,1,1,1,2,1,1]     => 54
[1,1,2,1,1,1,1,1,1,2]     => 52
[1,1,2,1,1,1,2,3]         => 34
[1,1,2,1,2,3,1,1]         => 40
[1,1,2,1,2,2,1,2]         => 38
[1,1,2,1,2,1,1,3]         => 36
[1,1,2,1,3,4]             => 20
[1,1,3,3,1,1,1,1]         => 46
[1,1,3,3,2,2]             => 26
[1,1,3,2,1,2,1,1]         => 44
[1,1,3,2,1,1,1,2]         => 42
[1,1,3,2,2,3]             => 24
[1,1,3,1,1,3,1,1]         => 42
[1,1,3,1,1,2,1,2]         => 40
[1,1,3,1,1,1,1,3]         => 38
[1,1,3,1,2,4]             => 22
[1,1,4,4,1,1]             => 30
[1,1,4,3,1,2]             => 28
[1,1,4,2,1,3]             => 26
[1,1,4,1,1,4]             => 24
[1,1,5,5]                 => 10
[2,2,1,1,1,1,1,1,1,1]     => 62
[2,2,1,1,1,1,2,2]         => 42
[2,2,1,1,2,2,1,1]         => 46
[2,2,1,1,2,1,1,2]         => 44
[2,2,1,1,3,3]             => 26
[2,2,2,2,1,1,1,1]         => 50
[2,2,2,2,2,2]             => 30
[2,2,2,1,1,2,1,1]         => 48
[2,2,2,1,1,1,1,2]         => 46
[2,2,2,1,2,3]             => 28
[2,2,3,3,1,1]             => 34
[2,2,3,2,1,2]             => 32
[2,2,3,1,1,3]             => 30
[2,2,4,4]                 => 14
[2,1,1,2,1,1,1,1,1,1]     => 60
[2,1,1,2,1,1,2,2]         => 40
[2,1,1,2,2,2,1,1]         => 44
[2,1,1,2,2,1,1,2]         => 42
[2,1,1,2,3,3]             => 24
[2,1,1,1,1,2,1,1,1,1]     => 58
[2,1,1,1,1,2,2,2]         => 38
[2,1,1,1,1,1,1,2,1,1]     => 56
[2,1,1,1,1,1,1,1,1,2]     => 54
[2,1,1,1,1,1,2,3]         => 36
[2,1,1,1,2,3,1,1]         => 42
[2,1,1,1,2,2,1,2]         => 40
[2,1,1,1,2,1,1,3]         => 38
[2,1,1,1,3,4]             => 22
[2,1,2,3,1,1,1,1]         => 48
[2,1,2,3,2,2]             => 28
[2,1,2,2,1,2,1,1]         => 46
[2,1,2,2,1,1,1,2]         => 44
[2,1,2,2,2,3]             => 26
[2,1,2,1,1,3,1,1]         => 44
[2,1,2,1,1,2,1,2]         => 42
[2,1,2,1,1,1,1,3]         => 40
[2,1,2,1,2,4]             => 24
[2,1,3,4,1,1]             => 32
[2,1,3,3,1,2]             => 30
[2,1,3,2,1,3]             => 28
[2,1,3,1,1,4]             => 26
[2,1,4,5]                 => 12
[3,3,1,1,1,1,1,1]         => 54
[3,3,1,1,2,2]             => 34
[3,3,2,2,1,1]             => 38
[3,3,2,1,1,2]             => 36
[3,3,3,3]                 => 18
[3,2,1,2,1,1,1,1]         => 52
[3,2,1,2,2,2]             => 32
[3,2,1,1,1,2,1,1]         => 50
[3,2,1,1,1,1,1,2]         => 48
[3,2,1,1,2,3]             => 30
[3,2,2,3,1,1]             => 36
[3,2,2,2,1,2]             => 34
[3,2,2,1,1,3]             => 32
[3,2,3,4]                 => 16
[3,1,1,3,1,1,1,1]         => 50
[3,1,1,3,2,2]             => 30
[3,1,1,2,1,2,1,1]         => 48
[3,1,1,2,1,1,1,2]         => 46
[3,1,1,2,2,3]             => 28
[3,1,1,1,1,3,1,1]         => 46
[3,1,1,1,1,2,1,2]         => 44
[3,1,1,1,1,1,1,3]         => 42
[3,1,1,1,2,4]             => 26
[3,1,2,4,1,1]             => 34
[3,1,2,3,1,2]             => 32
[3,1,2,2,1,3]             => 30
[3,1,2,1,1,4]             => 28
[3,1,3,5]                 => 14
[4,4,1,1,1,1]             => 42
[4,4,2,2]                 => 22
[4,3,1,2,1,1]             => 40
[4,3,1,1,1,2]             => 38
[4,3,2,3]                 => 20
[4,2,1,3,1,1]             => 38
[4,2,1,2,1,2]             => 36
[4,2,1,1,1,3]             => 34
[4,2,2,4]                 => 18
[4,1,1,4,1,1]             => 36
[4,1,1,3,1,2]             => 34
[4,1,1,2,1,3]             => 32
[4,1,1,1,1,4]             => 30
[4,1,2,5]                 => 16
[5,5,1,1]                 => 26
[5,4,1,2]                 => 24
[5,3,1,3]                 => 22
[5,2,1,4]                 => 20
[5,1,1,5]                 => 18
[6,6]                     => 6

-----------------------------------------------------------------------------
Created: Sep 21, 2011 at 16:41 by Chris Berg

-----------------------------------------------------------------------------
Last Updated: Jan 26, 2018 at 09:17 by Martin Rubey