a(n,k)  tabf head (staircase) for  A091534


    n\k         2            3           4           5          6         7        8      9      10    11  12
 
                    
    1           1            0           0           0          0         0        0      0       0     0   0
                      
    2          20           10           1           0          0         0        0      0       0     0   0
                      
    3        1120         1040         290          30          1         0        0      0       0     0   0
                       
    4      123200       161920       71320       14040       1340        60        1      0       0     0   0
                      
    5    22422400     37452800    22097600     6263040     958720     82800     4000    100       1     0   0
            
    6  6098892800  12222918400  8928102400  3257116800  675281600  84782880  6625920  322000   9400   150   1