Currently I am using the following formula:
=1 + (FLOOR((ROW()-2);5) / 5) + (FLOOR((ROW()-2);5) / 5) * 6
to change the numbers by 7 in different intervals and everything is working fine and you can see column A. But numbers should change by 15 for every 5th change and again the rest 4 changes should change by 7 (see in column B):
Is it possible to build a formula like that?
I changed your formula a bit to be shorter and a little safer:
The first part alone would be
=1+(INT((ROWS($C$1:C2)-2)/5)*7) and the added part takes care of the changes at the 5th change.
Hopefully, that will suit your needs better!
Couple of notes regarding the formula:
INT((ROWS($C$1:C2)-2)/5)*7 ^ ^ a b
a gives the frequency when 'change' of
b has to be applied. So in the above, 7 will be added after 5 rows, and extending the logic to the other part of the final formula, 8 is being added on top of the first 7 (total 15) added every 20 rows (i.e. after 4 changes each of 5 rows).
I believe what you are looking for boils down to adding another 8 every 20th row. This can be achieved by adding
FLOOR((ROW()-2)/20;1)*8 to your formula.