(n). ???; (n+1). PROFIT

Care to explain where did this meme come from?

1. Step 1
2. Step 2
3. Step 3
4. ???
5. PROFIT

I believe it'd be more like:
(n-n+1) Step 1
(n-n+2) Step 2
(n-n+3) Step 3
...
(n-1) Step (n-1)
(n) Step n (the profit step!)
If you go back to math class, you'll understand where this meme came from!