How do you categorize and count the number of documents created in a particular week?

Category field (Date format, "Created" is the field with the creation date):

        @adjust(Created;0;0;1-@weekday(Created);0;0;0)

Summation field (number format, that's right, just a number 1 to total up):

        1

This creates a view catagorized by a field that has the "previous Sunday" computed.
Set up category totals in the view for the summation field and you'll have what you want.

Applies to Notes Versions: 3, 4, 4.5, 4.6, 5