Ikleyn and greenstamps will probably tell you that any number will do, and
Ikleyn will likely chew you out for posting it.  But they probably have
never seen such sequences on tests given by employers to applicants, to test
their reasoning ability. The idea is to think of the simplest pattern that
works.

Start with 1, 
Now we have 1, add 1, get 2.
Now we have 2, multiply by 2, get 4.
Now we have 4, add 3, get 7.
Now we have 7, multiply by 4, get 28.
Now we have 28, add 5, get 33.
Now we have 33, multiply by 6, get 198.

Edwin