a(n,k) tabl head (triangle) for  A091039


  n\k      1       2          3            4              5             6          7       8      9     
  
    1      1       0          0            0              0             0          0       0      0      
                            
    2      3       1          0            0              0             0          0       0      0      
                           
    3      7       8          1            0              0             0          0       0      0      
                           
    4     15      52         30            1              0             0          0       0      0      
                           
    5     31     320        756          144              1             0          0       0      0      
                           
    6     63    1936      18360        17856            840             1          0       0      0      
                           
    7    127   11648     441936      2156544         619200          5760          1       0      0      
                       
    8    255   69952   10614240    259117056      447552000      29548800      45360       1      0      
               
    9    511  419840  254788416  31102009344   322444800000  149299200000 1854316800  403200      1