a(n,m) tabl head (triangle) for A090219 n\m 1 2 3 4 5 6 7 8 9 10 3 1 0 0 0 0 0 0 0 0 0 4 -1 4 0 0 0 0 0 0 0 0 5 1 -8 10 0 0 0 0 0 0 0 6 -1 12 -30 20 0 0 0 0 0 0 7 1 -64 600 -1600 1225 0 0 0 0 0 8 -1 80 -1000 4000 -6125 3136 0 0 0 0 9 1 -96 1500 -8000 18375 -18816 7056 0 0 0 10 -1 448 -21000 280000 -1500625 3687936 -4148928 1728000 0 0 11 1 -512 28000 -448000 3001250 -9834496 16595712 -13824000 4492125 0 12 -1 576 -36000 672000 -5402250 22127616 -49787136 62208000 -40429125 10648000 The rational factors needed to compute the formula for the n-th colum sequence of the (3,3)-Stirling2 array A078741 are b(n-2)= A090220(n-2)/Num(n-2)= [1, 6, 3, 1, 3/2, 3/10, 1/20, 3/70, 3/560, 1/1680, ...], n>=3.