a(n,m)  tabf head (staircase) for  A091752

    
    n\m          2             3             4             5           6           7         8         9      10      11    12  13  14
 
                     
    1            1             0             0             0           0           0         0         0       0        0    0   0   0
                      
    2            2            -2             1             0           0           0         0         0       0        0    0   0   0
                      
    3           40           -40            20            -6           1           0         0         0       0        0    0    0  0
                      
    4         2240         -2240          1120          -360          80         -12         1         0       0        0    0    0  0
                       
    5       246400       -246400        123200        -40320        9520       -1680       220       -20       1        0    0    0  0
               
    6     44844800     -44844800      22422400      -7392000     1786400     -332640     48720     -5600     490      -30    1    0  0
   
    7  12197785600  -12197785600    6098892800   -2018016000   493292800   -94174080  14463680  -1811040  184800   -15120  952  -42  1

    
    The sequence of row lengths for this array is [1,3,5,7,9,11,...]=A005408(n-1), n>=1.