This code runs fine on CoCalc:
def D(n):
if n <= 1:
return matrix([1])
l = [1,-1] + [0]*(n-2)
M = matrix(l)
i = 1
for _ in range(n - 1):
l = [i] + l[:-1]
M = M.stack(matrix(l))
i = 0
return M
for i in range(6):
A = D(i)
A
A.det()
But when I put it in the box at sagecell.sagemath.org there's no output. Why could this be?