# range, xrange and ellipsis iteration.

Consider the Maple lines

```
r := n -> (n-(n mod 2))/2:
seq(print(seq(r(n-k) + r(n+k), k = -n..n)), n=0..5);
```

Output:

```
0
1, 0, 1
2, 1, 2, 1, 2
3, 2, 3, 2, 3, 2, 3
4, 3, 4, 3, 4, 3, 4, 3, 4
5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5
```

I thought that the Sage equivalent is

```
r = lambda n: (n-(n%2))//2
for n in range(6):
[r(n-k) + r(n+k) for k in (-n..n)]
```

Unfortunately this is not the case. I get

```
"AttributeError: 'xrange' object has no attribute 'next'".
```

Is this a bug or a feature?

A possible workaround (?) is: for n in (0..5): [r(n-k) + r(n+k) for k in (-n..n)] or as tmonteil suggests below: for n in srange(6): [r(n-k) + r(n+k) for k in (-n..n)]