...which asserts an infinity kind of thing as it would pertain to a particular puzzle kind of thing -- any puzzle that postulates a sequence of given numbers and asks for one number -- the next number in the series.  The Differationale puzzle demonstrated how the algorithm [a] takes into account all of the given numbers without regard to how they were created and [b] derives a solution, which may or may not comply with what the puzzle-master had in mind when creating the puzzle, but [c] guarantees one and only one solution -- complete with a rationale. 

An unstated assumption is that the given numbers and the next number form a contiguous series, which is a feature exemplified by the Next Number puzzle and  thousands of challenges in the On-Line Encyclopedia of Integer Sequences (OEIS).

...which would be an OK kind of thing if the puzzle-master allows for non-integer solutions.

onventional challenges authorize only integers for number sequences.  Accordingly, linear interpolation will not always 'work'.  Solvers will be able to show that a reverse version of the differationale algorithm will always 'work'.  Let's call it the Missing Numbers algorithm. 

Hey, and the Missing Numbers algorithm is not limited to one and only one solution.  If you would like to figure out how that is possible, here is a question for you...