I want to mirror column "A" and through a formula keep adding to the sequence in bold.
Is there a way to have it so I don't need to manually input the numbers in sequence?
Thanks.
I want to mirror column "A" and through a formula keep adding to the sequence in bold.
Is there a way to have it so I don't need to manually input the numbers in sequence?
Thanks.
You could do this with an Apps Script Custom Function.
First, open a bound script by selecting Tools > Script editor, and copy the following functions to the script:
function MIRROR(until) {
  const sheet = SpreadsheetApp.getActive().getSheetByName("Question");
  const lastRow = getLastDataRow(sheet);
  const values = sheet.getRange(1, 1, lastRow).getValues();
  let series = values.slice(0, 4);
  let output = [];
  let currentNumber = values[values.length - 2][0] + 1;
  if (!until) currentNumber;
  for (; currentNumber <= until; currentNumber++) {
    output.push([[currentNumber],[series[1][0]],[""],[""]]);
  }
  return output.flat();
}
function getLastDataRow(sheet) { // Get last row in column A (see https://stackoverflow.com/a/53587462)
  var lastRow = sheet.getLastRow();
  var range = sheet.getRange("A" + lastRow);
  if (range.getValue() !== "") {
    return lastRow;
  } else {
    return range.getNextDataCell(SpreadsheetApp.Direction.UP).getRow();
  }
}
Once it is defined, you can use the function MIRROR the same you would any sheets built-in function. This function would accept a parameter in which you would specify until what number should the series continue. See, for example, this: