# How to insert function every X number of lines

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# How to insert function every X number of lines

I have a formula I'd like every 4 lines, i.e. D5 then D9 then D13. I have written it manually for D5 and D9 but when I highlight the rows from D5 to D9 and click the bottom right to extend the formula, it does not do what i expected. It instead goes D10 then D14/D15. Anyone know how I can do this? Thanks