First puzzle! I was inspired by this question to make my own. Props to the author for itching my brain!
Update: I double-checked the sequence, turns out it changed! I overlooked something which I have now made a note of in Hint 3. You are now trying to find the 13th number instead of the 14th.
Update 2: Updated the sequence again.
What is $x$ in this sequence?
This can be solved using only information that is found on Puzzling.SE.
Think about the linked question. This sequence can be solved in a similar way.
This sequence also changes, but not as often as the linked question.
The bigger numbers change more often than the smaller ones.
Key Hint (updated):
3 digits, 2 numbers, 1 op. All-time high.
Key Hint 2 (updated):
There is a code hidden in the Puzzling.SE link.
Key Hint 3:
All the information can be found on a single list of users on a single page.
Key Hint 4 (final?):
Integer division is involved. The code from Key Hint 2 describes the operation.