I have the following problem:

I'm working on a formula to calculate some network effects. The idea is that I have 450 "red users" and 6550 "blue users" which sums up to 7000 users in total. Now I would like to plot "picking x users (the same user cannot be picked twice, so this is sampling without replacement) and calculate the probability that at least 1 user is red". 

E.g for x = 3, that means I'm picking 3 random users out of 7000 and check if any of these are "red users"

The probability for having at least 1 red user is ***p = 1 - the probability all 3 picks are blue users*** and the probability for a blue user is equal to p = 6550/7000, right? 

Resulting in a probability for at least 1 red user:
**\* p = 1 - 6550/7000 \* 6549/6999 \* 6548/6998 \***

Therefore i came up with the formula:

`f(x) = e^-(1- sum of (6500-i)/(7000-i)); for i = 0, till x)`

What I've realized is that the curve is pretty edgy since it's just going from a value in ℕ to the next value in ℕ. 
Although adding decimal numbers wouldn't make that much sense since "picking 0,5 users or even 0,01 users" is just stupid, I would like to see the full graph in order to be able to compare the formula to some others. 

Is there any way I can implement this in python?

Best regards,

Korbi