18
18
It is 24+7 = 31
Continuing the sequence would be the the numbers 24, 31, 39.
The difference between consecutive numbers is 1, 2, 3, 4. So the next difference will be... Added to 13 gives...
18
18
18
13 20 12
It is 24+7 = 31
18 (3+1 4+2 6+3 9+4 13+5)
Continuing the sequence would be the the numbers 24, 31, 39.
Unless you specify the length of the sequence, it is infinite, and so no number completes it. Given no further information, I would say the next number is 18. However, check out the link to the OEIS which gives a number of alternatives.
The difference between consecutive numbers is 1, 2, 3, 4. So the next difference will be... Added to 13 gives...
The number which best completes the sequence below is:1 1 3 2 4 6 5 25 ?
4
The sequence appears to alternate between adding and subtracting numbers. The pattern seems to be +11, -7, +5, -2, +6. Following this pattern, the next number in the sequence would be +3 from the previous number, which would be 21.