This is brilliant, and shows how science works(according to Richard Feynman at least), and how any sort of decision making should work.
I'll let you take the test, and put a few blank lines before I share the answer, so as to not provide spoilers.
So the sequence was 2, 4, 8. Looks like either the next value is the double of the previous value, or it is the square of the previous value. I thought it was the latter. Confirmed it with the sequences 3, 9, 27 and 5, 25, 125. Was about to submit my answer, but for some reason tried the sequence 1, 1, 1. That sequence failed the test. Odd! It should've passed. So I tried a bunch of sequences and figured out that to pass the test the the next value needs to be greater than the preceding value.
A good illustration of confirmation bias. I should be more pessimistic about things than usual, it seems. At least towards my ideas and plans.