Answer:
[tex]\frac{62!}{56!}[/tex]
Step-by-step explanation:
We can either look at all 62 characters (2 * 26 in the alphabet and 10 digits), choose 6 of them, and add the fact that we care about their order - so multiply by 6! and we get [tex]\binom{62}{6}\cdot 6! = \frac{62!}{6!\cdot 56!} \cdot 6! = \frac{62!}{56!}[/tex]
Or, we can look atr all the permutations of all the characters and take into account that we DON'T care about the order of the 56 after the first six. Getting [tex]\frac{62!}{56!}[/tex] immediately.