*****************************************************************************
*       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: St000380

-----------------------------------------------------------------------------
Collection: Integer partitions

-----------------------------------------------------------------------------
Description: Half of the maximal perimeter of a rectangle fitting into the diagram of an integer partition.

Put differently, this is the smallest number $n$ such that the partition fits into the triangular partition $(n-1,n-2,\dots,1)$.

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

-----------------------------------------------------------------------------
Code:
def statistic(p):
    if p:
        return max( p[i]+i+1 for i in range(len(p)) )
    return 0

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

[]                        => 0
[1]                       => 2
[2]                       => 3
[1,1]                     => 3
[3]                       => 4
[2,1]                     => 3
[1,1,1]                   => 4
[4]                       => 5
[3,1]                     => 4
[2,2]                     => 4
[2,1,1]                   => 4
[1,1,1,1]                 => 5
[5]                       => 6
[4,1]                     => 5
[3,2]                     => 4
[3,1,1]                   => 4
[2,2,1]                   => 4
[2,1,1,1]                 => 5
[1,1,1,1,1]               => 6
[6]                       => 7
[5,1]                     => 6
[4,2]                     => 5
[4,1,1]                   => 5
[3,3]                     => 5
[3,2,1]                   => 4
[3,1,1,1]                 => 5
[2,2,2]                   => 5
[2,2,1,1]                 => 5
[2,1,1,1,1]               => 6
[1,1,1,1,1,1]             => 7
[7]                       => 8
[6,1]                     => 7
[5,2]                     => 6
[5,1,1]                   => 6
[4,3]                     => 5
[4,2,1]                   => 5
[4,1,1,1]                 => 5
[3,3,1]                   => 5
[3,2,2]                   => 5
[3,2,1,1]                 => 5
[3,1,1,1,1]               => 6
[2,2,2,1]                 => 5
[2,2,1,1,1]               => 6
[2,1,1,1,1,1]             => 7
[1,1,1,1,1,1,1]           => 8
[8]                       => 9
[7,1]                     => 8
[6,2]                     => 7
[6,1,1]                   => 7
[5,3]                     => 6
[5,2,1]                   => 6
[5,1,1,1]                 => 6
[4,4]                     => 6
[4,3,1]                   => 5
[4,2,2]                   => 5
[4,2,1,1]                 => 5
[4,1,1,1,1]               => 6
[3,3,2]                   => 5
[3,3,1,1]                 => 5
[3,2,2,1]                 => 5
[3,2,1,1,1]               => 6
[3,1,1,1,1,1]             => 7
[2,2,2,2]                 => 6
[2,2,2,1,1]               => 6
[2,2,1,1,1,1]             => 7
[2,1,1,1,1,1,1]           => 8
[1,1,1,1,1,1,1,1]         => 9
[9]                       => 10
[8,1]                     => 9
[7,2]                     => 8
[7,1,1]                   => 8
[6,3]                     => 7
[6,2,1]                   => 7
[6,1,1,1]                 => 7
[5,4]                     => 6
[5,3,1]                   => 6
[5,2,2]                   => 6
[5,2,1,1]                 => 6
[5,1,1,1,1]               => 6
[4,4,1]                   => 6
[4,3,2]                   => 5
[4,3,1,1]                 => 5
[4,2,2,1]                 => 5
[4,2,1,1,1]               => 6
[4,1,1,1,1,1]             => 7
[3,3,3]                   => 6
[3,3,2,1]                 => 5
[3,3,1,1,1]               => 6
[3,2,2,2]                 => 6
[3,2,2,1,1]               => 6
[3,2,1,1,1,1]             => 7
[3,1,1,1,1,1,1]           => 8
[2,2,2,2,1]               => 6
[2,2,2,1,1,1]             => 7
[2,2,1,1,1,1,1]           => 8
[2,1,1,1,1,1,1,1]         => 9
[1,1,1,1,1,1,1,1,1]       => 10
[10]                      => 11
[9,1]                     => 10
[8,2]                     => 9
[8,1,1]                   => 9
[7,3]                     => 8
[7,2,1]                   => 8
[7,1,1,1]                 => 8
[6,4]                     => 7
[6,3,1]                   => 7
[6,2,2]                   => 7
[6,2,1,1]                 => 7
[6,1,1,1,1]               => 7
[5,5]                     => 7
[5,4,1]                   => 6
[5,3,2]                   => 6
[5,3,1,1]                 => 6
[5,2,2,1]                 => 6
[5,2,1,1,1]               => 6
[5,1,1,1,1,1]             => 7
[4,4,2]                   => 6
[4,4,1,1]                 => 6
[4,3,3]                   => 6
[4,3,2,1]                 => 5
[4,3,1,1,1]               => 6
[4,2,2,2]                 => 6
[4,2,2,1,1]               => 6
[4,2,1,1,1,1]             => 7
[4,1,1,1,1,1,1]           => 8
[3,3,3,1]                 => 6
[3,3,2,2]                 => 6
[3,3,2,1,1]               => 6
[3,3,1,1,1,1]             => 7
[3,2,2,2,1]               => 6
[3,2,2,1,1,1]             => 7
[3,2,1,1,1,1,1]           => 8
[3,1,1,1,1,1,1,1]         => 9
[2,2,2,2,2]               => 7
[2,2,2,2,1,1]             => 7
[2,2,2,1,1,1,1]           => 8
[2,2,1,1,1,1,1,1]         => 9
[2,1,1,1,1,1,1,1,1]       => 10
[1,1,1,1,1,1,1,1,1,1]     => 11
[11]                      => 12
[10,1]                    => 11
[9,2]                     => 10
[9,1,1]                   => 10
[8,3]                     => 9
[8,2,1]                   => 9
[8,1,1,1]                 => 9
[7,4]                     => 8
[7,3,1]                   => 8
[7,2,2]                   => 8
[7,2,1,1]                 => 8
[7,1,1,1,1]               => 8
[6,5]                     => 7
[6,4,1]                   => 7
[6,3,2]                   => 7
[6,3,1,1]                 => 7
[6,2,2,1]                 => 7
[6,2,1,1,1]               => 7
[6,1,1,1,1,1]             => 7
[5,5,1]                   => 7
[5,4,2]                   => 6
[5,4,1,1]                 => 6
[5,3,3]                   => 6
[5,3,2,1]                 => 6
[5,3,1,1,1]               => 6
[5,2,2,2]                 => 6
[5,2,2,1,1]               => 6
[5,2,1,1,1,1]             => 7
[5,1,1,1,1,1,1]           => 8
[4,4,3]                   => 6
[4,4,2,1]                 => 6
[4,4,1,1,1]               => 6
[4,3,3,1]                 => 6
[4,3,2,2]                 => 6
[4,3,2,1,1]               => 6
[4,3,1,1,1,1]             => 7
[4,2,2,2,1]               => 6
[4,2,2,1,1,1]             => 7
[4,2,1,1,1,1,1]           => 8
[4,1,1,1,1,1,1,1]         => 9
[3,3,3,2]                 => 6
[3,3,3,1,1]               => 6
[3,3,2,2,1]               => 6
[3,3,2,1,1,1]             => 7
[3,3,1,1,1,1,1]           => 8
[3,2,2,2,2]               => 7
[3,2,2,2,1,1]             => 7
[3,2,2,1,1,1,1]           => 8
[3,2,1,1,1,1,1,1]         => 9
[3,1,1,1,1,1,1,1,1]       => 10
[2,2,2,2,2,1]             => 7
[2,2,2,2,1,1,1]           => 8
[2,2,2,1,1,1,1,1]         => 9
[2,2,1,1,1,1,1,1,1]       => 10
[2,1,1,1,1,1,1,1,1,1]     => 11
[1,1,1,1,1,1,1,1,1,1,1]   => 12
[12]                      => 13
[11,1]                    => 12
[10,2]                    => 11
[10,1,1]                  => 11
[9,3]                     => 10
[9,2,1]                   => 10
[9,1,1,1]                 => 10
[8,4]                     => 9
[8,3,1]                   => 9
[8,2,2]                   => 9
[8,2,1,1]                 => 9
[8,1,1,1,1]               => 9
[7,5]                     => 8
[7,4,1]                   => 8
[7,3,2]                   => 8
[7,3,1,1]                 => 8
[7,2,2,1]                 => 8
[7,2,1,1,1]               => 8
[7,1,1,1,1,1]             => 8
[6,6]                     => 8
[6,5,1]                   => 7
[6,4,2]                   => 7
[6,4,1,1]                 => 7
[6,3,3]                   => 7
[6,3,2,1]                 => 7
[6,3,1,1,1]               => 7
[6,2,2,2]                 => 7
[6,2,2,1,1]               => 7
[6,2,1,1,1,1]             => 7
[6,1,1,1,1,1,1]           => 8
[5,5,2]                   => 7
[5,5,1,1]                 => 7
[5,4,3]                   => 6
[5,4,2,1]                 => 6
[5,4,1,1,1]               => 6
[5,3,3,1]                 => 6
[5,3,2,2]                 => 6
[5,3,2,1,1]               => 6
[5,3,1,1,1,1]             => 7
[5,2,2,2,1]               => 6
[5,2,2,1,1,1]             => 7
[5,2,1,1,1,1,1]           => 8
[5,1,1,1,1,1,1,1]         => 9
[4,4,4]                   => 7
[4,4,3,1]                 => 6
[4,4,2,2]                 => 6
[4,4,2,1,1]               => 6
[4,4,1,1,1,1]             => 7
[4,3,3,2]                 => 6
[4,3,3,1,1]               => 6
[4,3,2,2,1]               => 6
[4,3,2,1,1,1]             => 7
[4,3,1,1,1,1,1]           => 8
[4,2,2,2,2]               => 7
[4,2,2,2,1,1]             => 7
[4,2,2,1,1,1,1]           => 8
[4,2,1,1,1,1,1,1]         => 9
[4,1,1,1,1,1,1,1,1]       => 10
[3,3,3,3]                 => 7
[3,3,3,2,1]               => 6
[3,3,3,1,1,1]             => 7
[3,3,2,2,2]               => 7
[3,3,2,2,1,1]             => 7
[3,3,2,1,1,1,1]           => 8
[3,3,1,1,1,1,1,1]         => 9
[3,2,2,2,2,1]             => 7
[3,2,2,2,1,1,1]           => 8
[3,2,2,1,1,1,1,1]         => 9
[3,2,1,1,1,1,1,1,1]       => 10
[3,1,1,1,1,1,1,1,1,1]     => 11
[2,2,2,2,2,2]             => 8
[2,2,2,2,2,1,1]           => 8
[2,2,2,2,1,1,1,1]         => 9
[2,2,2,1,1,1,1,1,1]       => 10
[2,2,1,1,1,1,1,1,1,1]     => 11
[2,1,1,1,1,1,1,1,1,1,1]   => 12
[1,1,1,1,1,1,1,1,1,1,1,1] => 13
[8,5]                     => 9
[7,5,1]                   => 8
[7,4,2]                   => 8
[5,5,3]                   => 7
[5,4,4]                   => 7
[5,4,3,1]                 => 6
[5,4,2,2]                 => 6
[5,4,2,1,1]               => 6
[5,3,3,2]                 => 6
[5,3,3,1,1]               => 6
[5,3,2,2,1]               => 6
[4,4,4,1]                 => 7
[4,4,3,2]                 => 6
[4,4,3,1,1]               => 6
[4,4,2,2,1]               => 6
[4,3,3,3]                 => 7
[4,3,3,2,1]               => 6
[3,3,3,3,1]               => 7
[3,3,3,2,2]               => 7
[9,5]                     => 10
[8,5,1]                   => 9
[7,5,2]                   => 8
[7,4,3]                   => 8
[5,5,4]                   => 7
[5,4,3,2]                 => 6
[5,4,3,1,1]               => 6
[5,4,2,2,1]               => 6
[5,3,3,2,1]               => 6
[5,3,2,2,2]               => 7
[4,4,4,2]                 => 7
[4,4,3,3]                 => 7
[4,4,3,2,1]               => 6
[3,3,3,3,2]               => 7
[9,5,1]                   => 10
[8,5,2]                   => 9
[7,5,3]                   => 8
[5,5,5]                   => 8
[5,4,3,2,1]               => 6
[5,3,2,2,2,1]             => 7
[4,4,4,3]                 => 7
[3,3,3,3,3]               => 8
[8,5,3]                   => 9
[7,5,3,1]                 => 8
[4,4,4,4]                 => 8
[8,6,3]                   => 9
[9,6,3]                   => 10
[8,6,4]                   => 9
[9,6,4]                   => 10
[8,5,4,2]                 => 9
[8,5,5,1]                 => 9
[7,5,4,3,1]               => 8
[8,6,4,2]                 => 9
[10,6,4]                  => 11
[10,7,3]                  => 11
[9,7,4]                   => 10
[9,5,5,1]                 => 10
[6,5,4,3,2,1]             => 7
[11,7,3]                  => 12
[9,6,4,3]                 => 10
[9,6,5,3]                 => 10
[8,6,5,3,1]               => 9
[11,7,5,1]                => 12
[9,7,5,3]                 => 10
[9,7,5,3,1]               => 10
[10,7,5,3]                => 11
[9,7,5,4,1]               => 10
[7,6,5,4,3,2,1]           => 8
[10,7,6,4,1]              => 11
[9,7,6,4,2]               => 10
[10,8,5,4,1]              => 11
[10,8,6,4,1]              => 11
[9,7,5,5,3,1]             => 10
[11,8,6,4,1]              => 12
[10,8,6,4,2]              => 11
[11,8,6,5,1]              => 12
[12,9,7,5,1]              => 13
[13,9,7,5,1]              => 14
[11,9,7,5,3,1]            => 12
[11,8,7,5,4,1]            => 12
[8,7,6,5,4,3,2,1]         => 9
[11,9,7,5,5,3]            => 12
[11,9,7,7,5,3,3]          => 12
[11,9,7,6,5,3,1]          => 12
[13,11,9,7,5,3,1]         => 14
[13,11,9,7,7,5,3,1]       => 14
[17,13,11,9,7,5,1]        => 18
[15,13,11,9,7,5,3,1]      => 16
[29,23,19,17,13,11,7,1]   => 30

-----------------------------------------------------------------------------
Created: Feb 09, 2016 at 12:26 by Christian Stump

-----------------------------------------------------------------------------
Last Updated: Feb 25, 2021 at 20:07 by Martin Rubey