Here are a number of misleading sequences. I have given the first few numbers of each sequence, and your mission, if you choose to accept it, is to guess the next number.
1. A Doubling Dilemma
1, 2, 4, 8, 16, ___?
Did you get 32 from doubling?
The answer is actually 31. Continue reading
A link to this article in pdf format: [pdf]
Here is a difficult probability question:
Suppose you are standing on an infinitely large square grid at the point (0,0), and suppose that you can see infinitely far but cannot see through grid points. Given a random grid point z = (x,y), where x and y are integers, what is the chance you can see z?
Here is the link to the paper [pdf].
Abstract: The main statistical result of this paper is that of the reddit users who have upvoted at least one post, 31.4% of them have upvoted only one post and, moreover, have been the only person to upvote it. Conversely, 22.6% of posts which have been voted on at all have received only downvotes and no upvotes. In addition, 67.4% of users are connected in a giant component of upvoting common posts, while 91.4% of posts are connected by having been upvoted by common users.
Epic Math 