a(n,m) tabl head (triangle) for  A091538


   n\m      0     1      2      3      4      5      6      7      8      9    10

                          
   0       1      0      0      0      0      0      0      0      0      0     0
                          
   1       0      2      0      0      0      0      0      0      0      0     0
                          
   2       0      3      4      0      0      0      0      0      0      0     0
                           
   3       0      5      6      8      0      0      0      0      0      0     0
                          
   4       0      7      9     12     16      0      0      0      0      0     0
                           
   5       0     11     10     18     24     32      0      0      0      0     0
                          
   6       0     13     14     20     36     48     64      0      0      0     0
                          
   7       0     17     15     27     40     72     96    128      0      0     0
                          
   8       0     19     21     28     54     80    144    192    256      0     0   
                           
   9       0     23     22     30     56    108    160    288    384    512     0 

  10       0     29     25     42     60    112    216    320    576    768  1024