No complicated set-up for this one! Quite simply, what number comes next and why?
2 4 6 9 11 15 20 ??

There's a much more elegent answer here.  I wont spoil the surprise too much, but notice the relationship between 4 and 6 as well as 9 and 11.  

A number further in the series could be 101.

 

Posted by B on 2004-11-11 10:15:21