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:

Position 6: 2^{^(6 – 1)} + 1 = 33

Position 7: 2^{^(7 – 1)} + 1 = 65

Position 8: 2^{^(8 – 1)} + 1 = 129

Position 9: 2^{^(9 – 1)} + 1 = 257

Position 10: 2^{^(10 – 1)} + 1 = 513