Math stuff

[TheSpy]

So, I have a a little problem. I have to calculate the amount of all possible combinations of some letters. It's not hard if the string can contain letters a, b and c with the length of 10 (3^10). This is a little more complicated. I have a string 20 characters long. It must contain 3xS, 3xB, 7xL and 7xP. How can I get the maximum amount of combinations for such a string pattern?

Thanks in advance.

[Mirosuke]

Yeah, that's your homework, not ours lol.
jk
well, not in a mood to resolve math problems > <

[panterr]

I think write them down is the only way....

[DumboDii]

I'm not 100% sure but I think it goes like this: (3x3x7x7)/20!

EDIT: I'm not sure at all now.

[SM-Count]

Just simplify the problem to what would happen if you had 2 'a', 2 'b', and 2 'c's then expand from there.

Spoiler!

Assuming letters are not unique:
n!/(3!*3!*7!*7!)

n! = all possible cases
3!*3!*7!*7! = correction for number of repeats (3 of two letters and 7 of 2 other letters)

[TheSpy]

Just simplify the problem to what would happen if you had 2 'a', 2 'b', and 2 'c's then expand from there.

Spoiler!

Assuming letters are not unique:
n!/(3!*3!*7!*7!)

n! = all possible cases
3!*3!*7!*7! = correction for number of repeats (3 of two letters and 7 of 2 other letters)

Thanks, you helped me out a lot.