Clear[f,x,n,NumTimes]
f[x_]=x^3-4x^2-1

x[0]=5.0

NumTimes=5;

For[n=0, n<=NumTimes,
x[n+1]=x[n]-f[x[n]]/f'[x[n]];
n=n+1]

Table[{n,x[n]},{n,1,NumTimes}]

TableForm[Table[{n,x[n]},{n,1,NumTimes}]]