a(n,k)  tabf head (staircase) for  A078741


  n\k    3       4         5          6           7           8           9         10         11        12      13      14      15   16   17   18
 

   1     1       0         0          0           0           0           0          0          0         0        0      0       0    0    0    0
                   
   2     6      18         9          1           0           0           0          0          0         0        0       0      0    0    0    0
                   
   3    36     540      1242        882         243          27           1          0          0         0        0       0      0    0    0    0
                  
   4   216   13608     94284     186876      149580       56808       11025       1107         54         1        0       0      0    0    0    0
         
   5  1296  330480   6148872   28245672    49658508    41392620    18428400    4691412     706833     63375     3285      90      1    0    0    0
   
   6  7776 7954848 380841264 3762380016 13062960720 20679463296 17312948100 8401432428 2505405330 476080650 58750461 4722273 243360 7695  135    1


  The sequence of row lengths for this tabf array is [1,4,7,10,13,16,...].