SE-SKOLORNAS 1974 Problem 3

Let $a_1=1$ , $a_2=2^{a_1}$ , $a_3=3^{a_2}$ , $a_4=4^{a_3}$ , $\dots$ , $a_9 = 9^{a_8}$ . Find the last two digits of $a_9$ .

Dataset text AI-MO AoPS. Quoted with source.

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.