How do I create a custom fill series for dates?

[Jeff]

I want to create a custom fill series for dates. Example: For the first
four (4) cells I want 5-1-07, the next four (4) cells I want 5-2-07, the next
four (4) cells in want 5-3-07,... I want this to continue in series for as
long as I drag down "the fill handle".

 

[Max]

One way ..

Put in any starting cell, eg in B2:
= --"5Jan2007"+INT((ROW(A1)-1)/4)
Format B2 as date to taste, then copy down as far as required