a(n,m) tabl head (triangle) for A089504 n\m 1 2 3 4 5 6 7 8 1 1 0 0 0 0 0 0 0 2 6 1 0 0 0 0 0 0 3 36 30 1 0 0 0 0 0 4 216 756 90 1 0 0 0 0 5 1296 18360 6156 210 1 0 0 0 6 7776 441936 387720 31356 420 1 0 0 7 46656 10614240 23705136 4150440 119556 756 1 0 8 279936 254788416 1432922400 521757936 29257200 373572 1260 1