Increment formula by mutlipel rows

Hello,

I have a very rudimentary question.

I have a formula that I want to increment by 7, for each row following the formula, how can I accomplish this? I have hundreds of rows so it is would be very efficient for me to manually increase each formula by 7

Original formula
=Sheet2!A1

Want it to look like
=Sheet2!A1
=Sheet2!A8
=Sheet2!A15
=Sheet2!A22
......

Try this ...

=INDEX(Sheet2!A:A,ROWS($A$1:A1)*7-6)