27
There are two interwoven series.
A) 2,5,10,17 2 + 3 = 5 : 5 + 5 = 10 : 10 + 7 = 17
Each term takes the previous term and adds increasing odd numbers starting with 3.
B) 9,13,19....and then 27 9 + 4 = 13 : 13 + 6 = 19 : 19 + 8 = 27
Each term takes the previous term and adds increasing even numbers starting with 4.
27.
The next figure would be 21, followed by 11 & 10.
22
It's, 7n+6
This is a peculiar number sequence which follows the following rule: +7, -4, +8, -3, +9, -2... The next few functions would be +10, -1, +11, -0 And thus the next few numbers in the sequence would be 17+10=27, 27-1=26, and so on. The sequence in total goes 2, 9, 5, 13, 10, 19, 17, 27, 26, 37, 37.
27.
The next figure would be 21, followed by 11 & 10.
22
18. The pattern is add 5, then subtract 1.
The next number in the sequence is 27.
It's, 7n+6
18
This is a peculiar number sequence which follows the following rule: +7, -4, +8, -3, +9, -2... The next few functions would be +10, -1, +11, -0 And thus the next few numbers in the sequence would be 17+10=27, 27-1=26, and so on. The sequence in total goes 2, 9, 5, 13, 10, 19, 17, 27, 26, 37, 37.
The sequence 14567911 appears to be a series of increasing odd numbers: 1, 5, 7, 9, and then jumps to 11. Following this pattern, the next odd number after 11 is 13. Therefore, the next number in the sequence is 13.
20
41
The next number is 27. Nice puzzle! The reason is on discussion page, for those who are still working on it.