The solution lies with using Excel's array feature to traverse a data list automatically and extract missing sequential numbers, even if the number list is out of order.

How to Make Excel Continue to Count Up for Each Row. Entering a series of sequential numbers into an Excel spreadsheet, one per row, can be a time-consuming and repetitive task.

Learn Excel’s Sequence function to generate numbers, dates, and custom formats effortlessly. Work smarter and faster with this guide ...

You can sum a series of numbers in Microsoft Excel manually by typing in a simple formula, or automatically with a tool.

Microsoft Excel's new dynamic array functions make complex calculations easier than ever before.