It is not possible to mix data tables and scenario outlines. Instead I'd rewrite your scenario as follows:
When I visit the URL <base>/<page>/<questionNumber>/<questionName>
Then the browser contains test <questionNumber>
Examples:
| base | page | questionNumber | questionName |
| http://www.stackoverflow.com | questions | 123 | specflow-q1 |
| http://www.stackoverflow.com | questions | 456 | specflow-q2 |
| http://www.stackoverflow.com | questions | 789 | specflow-q3 |
Inside the "When I visit the URL" step definition you'd construct the URL from the passed-in table parameter (which is what you are doing currently).
Whilst "base" and "question" values are repeated in the "Examples" section, it is clear to see what exactly is being tested. A non-technical user (e.g. business user) will also be able to easily understand what this test is trying to achieve too.