I'm assuming 47 is in B2, so in C2 use

=IF(MAX(Data!D:D)=B2+1,B2+1,"")

"Beertje" wrote:

My first sheet (called Data) contains following information:
Col A Col B Col C Col D
Part 1 5 Date =weeknum(C1) i.e. 46
Part 2 6 Date 46
Part 1 4 Date 46
Part 1 5 Date 47
This list is filled with more rows with the same week number.

On another sheet (called Summary) I try to summarize the data like following:
Col A Col B Col C Col D
46 47 Formula Formula

I need a formula for this row, which automatically fills in the next week
number if it shows up in my database (only column per week). I.e. as soon as
in column D of the Data sheet the next week number shows up (here 48) it is
automatically shown in Col C of my summary sheet etc.

Who can help me with this formula?