Anyone good with maths?

[dbftbs]

Alright so I'm kinda stupid and would like some help to solve this problem lmao.

 

Suppose Lisa has a bunch of 1x1 cubes. She is building a podium. The top layer is always 2 x 3 and the layer below has cubes sticking out 0.5 on each of the 4 sides (this is true for every layer). Write a summation formula to calculate the cubes needed for layer N.

 

I just don't know what the fuck is the formula lmao and I can't think for shit I even tried making it in Minecraft pls help me :joduscry: