Repeat at regular interval after first occurrence

[MrNal]

I have a data like below. Lets say for the first occurrence in the First row, I use a formula to specify that a value, say 55, must be inputted in Feb and the data inputted every 3 months subsequently i.e the next one in May. I tried using mod and count but not working as I want it to. Will be grateful for assistance on how to achieve what I described.


Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
First 1st occurrence in Feb...repeat every 3 months thereafter
2nd 1st occurrence in April...repeat every 4 months after

 

[MrNal]

Eventually figured it out. In case useful for someone else this is what I did. Used IF, SUM and OFFSET to accomplish task. Along the lines... IF(SUM(OFFSET(Previous Cell,0,-2,,3))=0, perform action, 0). Since will only SUM to 0 every 3 cells (3 months), action get performed every 3 months.

 

[FDibbins]

If you only have 12 months across(A:L), and may rows down, why dont you just do something like...
B2=55
C2=66
D2=77
E2=B2
then just copy that across as needed.
You can then copy from E2:L2 down as needed. Your current formula, while correct, will be very inefficient on a large number of rows.

 

[MrNal]

Unfortunately, have 20 years of monthly data across and not just 12 months. Also, before this particular action of repeating every 3 months (actual frequency depends on the row) , there are actually other actions that are performed in the beginning.