The letter H. It completes the list of letters that are vertically symmetrical. In other words, you can fold the top half of the letter over the bottom half and everything lines up.
I hesitated to add this because it’s poorly worded, ambiguous and the answer could be almost anything. I prefer teasers with a single answer, but there you go.
If you came up with a different answer and can explain how you did it, don’t think you’re wrong. It’s probably just as valid. Feel free to share yours in the comments.
My answer for the first number is 2.
Here’s how I got it.
The generic rule for a number in the sequence is: 2^(n – 1) + 1, where n is the position in the sequence.
Note: The teaser doesn’t specify the position of 17. In this case, it’s fifth.
Position 1: (so n = 1) is 2^(1 – 1) + 1 = 2
Position 2: 2^(2 – 1) + 1 = 3
Position 3: 2^(3 – 1) + 1 = 5
Position 4: 2^(4 – 1) + 1 = 9
Position 5: 2^(5 – 1) + 1 = 17
For the curious, the next 5 numbers of the sequence would be:
Smoke. It rises then slowly dissipates in the air. Smoke signals send messages and incense is used in religious ceremonies. Anyone who’s sat at a bonfire knows smoke in your eyes can make you cry when the wind changes direction. Smoked meats are a tasty treat, but if you see heavy smoke (i.e. from a fire) then run. Or stop drop and roll if the fire already caught you.
Yes, there’s a 4th of July in every country. Of course they don’t treat it as a holiday as citizens of the United States do, but that’s not what was asked.
Alcohol. People have a drink to celebrate, but also drink to hide their shame. Lastly, drunk driving is a crime.
A mask is also a valid answer. They can be used to celebrate Halloween or at dress-up parties, a mask can hide your shame and masks are used by thieves.
Update: This one has more valid answers than I thought. Money, drugs and night also work.