# Divisibility

To find numbers of the form 7aaa that are multiples of 7, I use:

```
sage:print [a for a in [0..9] if (7000+111*a)%7==0]
[0, 7]
```

I do not know how to write for 7|7abc.

Thanks.

Divisibility

To find numbers of the form 7aaa that are multiples of 7, I use:

```
sage:print [a for a in [0..9] if (7000+111*a)%7==0]
[0, 7]
```

I do not know how to write for 7|7abc.

Thanks.

0

Hello,

There are various solutions. To generate the list of numbers of the form 7abc, you can use one of:

```
sage: numbers0 = range(7000,8000)
sage: numbers1 = [7000 + x for x in range(1000)]
sage: numbers2 = [7000 + a*100 + b*10 + c for a in range(10) for b in range(10) for c in range(10)]
```

Then you can check divisibility the very same way you did. But note that there is a faster way since x is a multiple of **7** if and only if **x+7** is a multiple of 7. So once you find one, you only need to go 7 by 7.

Is that ok ?

Vincent

0

I tried:

```
sage: a=range(7000,8000)
sage: print[a if a%7==0]
File "<ipython-input-30-590163f2a51e>", line 1
print[a if a%Integer(7)==Integer(0)]
^
SyntaxError: invalid syntax
```

I find a solution:

```
print [a for a in [7000..7999] if a%7==0]
```

Thank you for support.

Please start posting anonymously - your entry will be published after you log in or create a new account.

Asked: ** 2014-10-18 17:32:22 +0200 **

Seen: **2,116 times**

Last updated: **Oct 18 '14**

Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.

I reedit your question. Please double check that it is all right. It was not very clear.

Thank you for edit.