For how many integers $a$ satisfying $1 \le a \le 23$ is it true that $a^{-1} \equiv a \pmod{24}$?
1 - The mmi = 1 [mmi - stands for "Modular Multiplicative Inverse" ] 5 - The mmi = 5 7 - The mmi = 7 11 - The mmi = 11 13 - The mmi = 13 17 - The mmi = 17 19 - The mmi = 19 23 - The mmi = 23
Count them and you get a == 8
