They should all be safe from row insertions.
=INDEX(Sheet1!$A:$A,(ROW(A1)-1)*21+1,1)

That one isn't.

=INDEX(Sheet1!$A:$A,(ROWS($1:1)-1)*21+1)

Biff

"Harlan Grove" wrote in message
ups.com...
Zack Barresse wrote...
Interesting. I've used the two before, but not in such a fashion/context.
I know there are many, many permutations which you can use. Such as ...
...

You're right. I confused your ROW(A1) with ROW(). Sorry.

Not a problem for this particular formula, but there are situations in
which ROW(...) can cause problems that ROWS(...) avoids when used in
INDIRECT or OFFSET calls inside other function calls.