23. They're all prime numbers
22
24
17?
15
21. Add the last 2 numbers to get the next.
21. This is the Fibonacci series.
34. Each number is the sum of the two preceding numbers. This is called the Fibonacci Sequence.
The next number in the sequence 5-7-13-31 is 69.
From the pattern (n + 4, n + 2, n + ?) I would say the next following number is 20 (n + 1).
The nest number in the sequence is 18. Note that the difference between each number and the next number in the sequence follows the simple sequence of 1,2,3,4. Obviously the next in the sequence of increases is 5, so 13+5=18.
The sequence 0112358 represents the Fibonacci sequence, where each number is the sum of the two preceding ones. The next number in this sequence is 13, as it is the sum of the last two numbers, 5 and 8. Thus, the next number is 13.
The next number in the sequence is 27.