Hello Simone,
Yes, it is possible. You will need to use a scheduled task executed every Monday. In the task conditions, use the below script to determine whether the next Saturday matches the specified number. In the script, the $requiredNumber variable specifies the number that should be matched.
$requiredNumber = 3 # TODO: modify me
$date = (Get-Date).AddDays(-5)
$weekdayCalc = [int][Math]::Floor($date.Day / 7)
$weekdayNum = if ($date.Day %% 7 -eq 0) {$weekdayCalc} else {$weekdayCalc+1}
$Context.ConditionIsMet = $requiredNumber -eq $weekdayNum
Finally, the scheduled task will look like the following: