You can do this in Haskell easily without a timeout, how you filter them is the critical part.

For example how would you do this in Haskell :

-generate all the numbers from 1 to 50 bazillion
-filter the numbers which are equal to 69
-return the remaining list

That's the wrong question. The correct question is, it's not specified at all how 1 is handled.

I've changed the input range to n > 1. Given that 1 should be omitted it doesn't make sense for 1 to be the input anyway.

I don't know how to work it out

Yeah. Doing that hurt a little.

Great job!

@fabs,
Thanks. Is the problem fixed?

Very nice! I changed the initial function type declaration (from String -> String to String -> Int -> String) so now it works. It could still use some test cases.