» Retrieving Every nth Value In a Range

Problem:

Creating a new list (List2), containing every 3rd value from List1 (Column A).

Solution:

Using the INDEX function as follows:
=INDEX($A$2:$A$13,(ROW()-2)*3+3)
Enter the formula in the first cell of List2, and copy it down.

List1___List2
A_______C
B_______F
C_______I
D_______L
E
F
G
H
I
J
K
L
Screenshot // Retrieving Every nth Value In a Range