Most spreadsheet users, when faced with a repetitive pattern like X15Y, X20Y, and so on, reach for the fill handle and hope for the best. That approach works for simple sequences, but it breaks the moment you need a variable prefix or suffix stored in a separate cell. The Reddit user who asked this question spotted a real gap: spreadsheets should let you build custom sequences from live references, not just static starting values. Their problem is common, and the solution is straightforward once you know where to look.
The core insight here is that you do not need a script or a macro to chain text around a numeric step. You need a formula that treats the prefix cell, the suffix cell, and an incrementing number as three independent pieces. In Google Sheets or Excel, that means using the ampersand or CONCATENATE to glue them together, with the middle piece coming from a formula like `ROW()*5+10` or a simple arithmetic step. For the user's example, starting at 15 and increasing by 5 up to 150, you can write `=$A$1 & (ROW(A1)*5+10) & $B$1` in the first cell, then drag down. The prefix and suffix stay locked, the number climbs in predictable increments, and the whole sequence updates automatically if you change either end piece.
This is not about a new feature. It is about recognizing that spreadsheets already have the tools for this kind of dynamic construction. The frustration the user described, wanting to type a prefix in one place and have a whole column respect it, is a symptom of thinking in static rows instead of formulas. Once you shift to a formula-first mindset, the same pattern applies to product codes, invoice line items, or any repeated label that needs variable text on both sides. The prefix cell becomes a configuration point; the suffix cell becomes another. The column becomes a living document.
What matters here is that the user's request is entirely practical and immediately solvable with existing spreadsheet functions. No plugins, no AI, no learning a new interface. If you are building a sheet that generates labels or identifiers, take five minutes to set up a prefix cell and a suffix cell before you type a single value. That small investment pays back every time you need to change the format. The user who posted this question is already thinking the right way, now they just need the formula to match their intent.