x = 10 s1 = [[0]*(i+1) for i in range(x)] # boundary conditions, n == k -> 1, k == 0 && n > 0 -> 0 for n in range(x): s1[n][n] = 1 for n in range(2,x): for k in range(1,n): s1[n][k] = (n-1)*s1[n-1][k] + s1[n-1][k-1] for r in s1: for c in r: print(c, end=' ') print()