I have given up and hope for some help.
I need at custom function in this format
WeeksVisit ( starting_date ; Interval )
It should be recursive and calculate the week numbers for the coming visits.
if we enter the date 13/8/6 (today) - and the interval of 90 the result should be 32¶5¶18¶31
32 ( week for today )
5 ( for date 13/11/4 90 days from today)
18 ( for date 14/2/2 - 90 days from last date )
31 ( for date 13/8/1 - 90 days from last date )
Now it shoud stop - only show week numbers for the coming year.
For info I have calculated the week-numbers with this formula WeekOfYearFiscal ( date ; 2 )
(belive this is how it is done in Europe)
Hope somebody can help out here
Best regards Lars