index(IJK ) propagation

Hello everyone,

I want to know, how IJK index gonna propagate for 2D model?

I tried to see the relation between cells number and the output for each iteration I found that

1x1 ==> 9
2x2==> 16
3x3==>25
4x4==>36
5x5==>49
6x6==>64

I am not able to understand the question as worded.