Question 85
A sequence is defined by $a_{0}=1$ and $a_{n}=2^{a_{n-1}}$ for $n \geq 1$. What is the last digit (in base 10) of $a_{15}$?
MathNet 2002 — Part 02 Question 85
Math Olympiad Vault · MathNet 2002 — Part 02
Math Olympiad Vault · MathNet 2002 — Part 02