Question

n (level 0) = 1
n (level 1) = 4
n (level 2) = 13
n (level 3) = 27

what is the n level ?
it means n of any level ..
I need an equation, pls ?

Answer 1

I can come up with a cubic polynomial that fits the data, but somehow I don't think that's what you're after. Are you just given a table like

0 1
1 4
2 13
3 27

and asked to come up with a rule? It's not an arithmetic or geometric sequence, so it seems a bit complicated.