Can I make array position A(12) into a variable A(12*n) ?

[Guest]

I am constantly adding data to my array and want formulas that can expand
with the data. Data is added by weeks. The first number is at A1 how can I
put in a formula that it needs to sum A1, A12,A24,depending on the week? Such
as A(1*n) where n is the week number.

Thanks....Paul

 

[Guest]

Perhaps something like this might work for you, or at least point you in the
right direction:

=A1+SUMPRODUCT((MOD(ROW(A1:A1000),12)=0)*(A1:A1000))

This will sum A1 and all cells in column A whose row number is evenly
divisible by 12.

HTH,
Elkar