What's going wrong with my code for Euler Project #1? : <p>Can anyone tell me where it is my program is going wrong here? I just don't see it...</p>

<pre><code>x_3 = []
i=0
while 3*i &lt; 1000:
    sum_3 = 3*i
    x_3.extend([sum_3])
    i += 1

x_5 = []
j = 0
while 5*j &lt; 1000:
    sum_5 = 5*j
    j += 1
    x_5.extend([sum_5])

answer = sum(x_5) + sum(x_3)
print(answer)
266333
</code></pre>

<p>Which is not correct. </p>
