>>13988733Number of possible elements per position: 26 (letters) + 10 (numbers) = 36
Number of elements in a sequence: 5
Total possible sequences: 36^5 (repeats assumed)
Given a sequence of 5 elements, how many ways can that sequence be arranged: 5! = 120
Therefore, there are 120 possible ways out of 36^5 total sequences that what happened to you could happen.
Therefore, the probability of what happened to you was: 120/36^5 ~ 2*10^-6.
Seems unlikely, but consider that 4chan has > 20 million unique visitors per month:
https://www.4chan.org/advertiseand 900k - 1mil posts per day. So there may at least 25 million posts from 20 million unique users per month.
Let's assume the 1% rule holds for 4chan:
https://en.m.wikipedia.org/wiki/1%25_rule_(Internet_culture), to the degree that only 1% of users make at least 2 posts a month.
0.01 * 20mil = 200k
Given the other 19.8mil make 1 post a day, that, this means that the 200k, 1% users roughly make 25mil - 19.8mil = 5.2mil posts per month. Let's assume all 200k make the same number of posts (for simplification purposes), i.e. 5.2mil/200k = 26 posts per 1% user.
If a user makes N posts, there are N - 1 pairs of posts that the user makes ((1,2), (2,3), ..., (N-1, N)). Therefore, a total of 200k*25 = 5mil pairs of posts, where each pair is from some user.
So in a month, the probability of what happened to you *not* happening to all of this 5mil pairs of posts is: (1 - 120/36^5)^5000000 ~ 5*10^-5
So the probability of this happening to at least 1 person in a month is: 1 - (1 - 120/36^5)^5000000 ~ 99.995%
Even if we assume a uniform 150k pairs of posts a day (replace 5000000 with 150000), we get ~25% chance it happened to someone today.
If
>>13993900 is right with 20 characters, then the above becomes (replace 36 with 20), ~ 99.9999999...% (at least 20 9's) of what happened to you happening to at least 1 person in a month and a 99.6% chance of this happening to someone in a day.
So pretty likely.
I think :^)
