General Doubt

Question

Convert this language to Push Down Automata – {a^n u | u ∈ {a, b}*, |u| = n, n ≥ 0}

Answer 1

The Language of PDA, $L=\{e,ab,aa,a^2aa,a^2ba,a^2ab,a^2bb ,a^3aba,...\}$. 

So it is basically of the form $a^n$(any $n$ length string).