SpreadsheetLIVE employs a "drag-and-fill" feature. Essentially, you are able to automatically fill a series of vertically adjacent cells based on a pattern. For instance, if "A1:A3" are filled with "1:3", you can select all "A1:A3", move your cursor to the bottom right of the selected cells and drag downwards. The series will be completed to the point where you drag your cursor. Therefore, if you drag down to cover cell A6, then cells "A1:A6" will be filled with "1:6".
Image 1 - An example of the drag-and-fill feature (as described in the example above).
This also works with formulas including cell links. For example, if cell "A1" had the formula "=B1-10", then dragging the bottom right of the cell downwards to cell "A4" would automatically fill the intermediate cells with formulas "=B2-10", "=B3-10" and "=B4-10".
Image 2 - An example of the drag-and-fill feature (as described in the example above).