2:     -1        -1         1         1     
   3:          -2   -1         1    2         1    2
   4:     -3        -1         1         3         1     
   5:     -2   -3   -1         1    3    2    4         1    3
   6:               -1         1                   5         1     
   7:     -5   -4   -1         1    4    5    2    3    6         1    4
   8:     -3        -1         1         3         5         7         1     
   9:          -5   -1         1    5         7    2         4    8         1    5
  10:     -7        -1         1         7                   3         9         1     
  11:     -4   -6   -1         1    6    4    3    9    2    8    7    5   10         1    6
  12:               -1         1                   5         7                  11         1     
  13:     -9   -7   -1         1    7    9   10    8   11    2    5    3    4    6   12         1    7
  14:     -5        -1         1         5         3                  11         9        13         1     
  15:          -8   -1         1    8         4             13    2             11         7   14         1    8
  16:    -11        -1         1        11        13         7         9         3         5        15         1     
  17:     -6   -9   -1         1    9    6   13    7    3    5   15    2   12   14   10    4   11    8   16         1    9
  18:               -1         1                  11        13                   5         7                  17         1     
  19:    -13  -10   -1         1   10   13    5    4   16   11   12   17    2    7    8    3   15   14    6    9   18         1   10
  20:     -7        -1         1         7                   3         9        11        17                  13        19         1     
>>