How may I find the pattern of a table.

Question

I have the following table:

Processes | Failures:
12            5
15            6
18            7
19            8
21            9
24            10
27            11
28            12
30            13
33            14
36            15
37            16
39            17

and I want to know how many processes I need to endure 1 failure in average.

Which should become something between 2f+1 and 3f+1 processes for f failures.

I also have this table:

Pr. Msg
12  28
15  40
18  54
19  70
21  88
24  108
25  130
27  154

Which should describe how many messages we need to send for n processes (message complexity) - which should be somewhere between O(n) and O(n^2) But I wasn't able to find a single "simple" formula describing these rows.