Google-sheets – way to select a range for a SWITCH statement

Here is a (stand-alone) script that attempts to do this. An important caveat: scripts are subject to quotas, one of which is: no more than 250 spreadsheets created per day. So the script will be halted before finishing the job if you run it in the present form. You may want to change the upper bound to 671+250, and rerun the script with different starting values on different days.

The logic is simple: the file number 670 is used as a prototype for all of them, via makeCopy method. Each newly created file is then modified via SpreadsheetApp, and its URL is recorded in master sheet.

function copy() {
  var masterId = ' ID of your master spreadsheet';
  var fileId = ' ID of your 670 file ';

  var master = SpreadsheetApp.openById(masterId);
  var masterSheet = master.getSheetByName('list of URLs');
  var file = DriveApp.getFileById(fileId);
  for (var i = 671; i < 8192; i++) { 
    var newFile = file.makeCopy('file'+i);
    var ss = SpreadsheetApp.open(newFile);
    var sheet = ss.getSheets()[0];    // assuming you want the first sheet
    sheet.getRange('A6').setValue(i);
    masterSheet.getRange('L' + (i+1)).setValue(ss.getUrl());
  }
}

If the string you're starting with, say 3 1 0, is in cell A1, the following function generates a random string such as 1 4 1.

=left(join(" ", {randbetween(1,4); randbetween(1,4); randbetween(1,4); randbetween(1,4)}), len(A1))

The idea is to generate an array of four random numbers, join it into a space-separated string, and then cut the part of the string of the same length as the input.