Let's first identify the number of squares in each stage:
Stage 1: 7 squares.
Stage 2: 14 squares.
Stage 3: 21 squares.
If we notice the sequence, we notice that it increases by 7 per stage, therefore:
Stage N: N*S
Where S is always equal to 7.
Foe example, in the stage 4:
Stage 4: 4*7 = 28 squares.
The equation is:
7*N
