Math contains numerous sequences. A conventional question includes decoding a sequence of numbers to find a common pattern and then figuring out the next number in the sequence. In this particular sequence we find that the difference between subsequent numbers results in an odd number.
These numbers are arranged in a decreasing order of magnitude. The last one is 17. So, conventionally, the next number in the differences should be 15. This automatically gives us the next number of the sequence, which is 64. You can find these patterns by subtracting individual numbers from each other and figuring out the patterns from the answer.