Firstly type the formula of A1385 in Cell. Like any other dynamic array function SEQUENCE is only available in the latest builds of Excel 365 that support dynamic arrays. For more information about copying formulas see Copy and paste a formula to another cell or worksheet.
Use dollar signs to keep one cells formula the same regardless of where it moves.
The easiest way to apply a formula to the entire column in all adjacent cells is by double-clicking the fill handle by selecting the formula cell. Simply select the cell containing the formula and the cells you want to fill with that formula. Click on the Paste Special option. You can also fill formulas using the Fill command on the ribbon.