Number of the week (between 0 and 53) corresponding to the specified date.

Date to use. This date can correspond to:

• a character string in YYYYMMDD format (YYYY corresponds to the year, MM to the month and DD to the day).
• Versions 24 and later
  a character string in YYYYMMDDHHMMSSCC format (YYYY corresponds to year, MM to month, DD to day, HH to hour, MM to minutes, SS to seconds and CC to hundredths of a second (use CCC for milliseconds). In this case, only the date is taken into account.
  New in version 24
  a character string in YYYYMMDDHHMMSSCC format (YYYY corresponds to year, MM to month, DD to day, HH to hour, MM to minutes, SS to seconds and CC to hundredths of a second (use CCC for milliseconds). In this case, only the date is taken into account.
  a character string in YYYYMMDDHHMMSSCC format (YYYY corresponds to year, MM to month, DD to day, HH to hour, MM to minutes, SS to seconds and CC to hundredths of a second (use CCC for milliseconds). In this case, only the date is taken into account.
• a Date variable.
• Versions 24 and later
  a DateTime variable. In this case, only the date is taken into account.
  New in version 24
  a DateTime variable. In this case, only the date is taken into account.
  a DateTime variable. In this case, only the date is taken into account.