Number of steps needed to find an arbitrary pattern

Question

For example a pattern could be 1,3,5 and you could say the next number is 7 because you add 2 each time. But what if you are given just the number 1 or 1,3? You can't say that the pattern is you add 2 each time confidently right? Another example are raven's progressive matrices, https://en.wikipedia.org/wiki/Raven%27s_Progressive_Matrices where you are to identify the next element in the pattern, and it seems like most commonly are 3x3 grids, but how are these determined? For any arbitrary pattern, is there a needed number of steps to determine the next element in the list (and thus the pattern)?