you are mentally retarded. the probabability of someone showing up once out of 10 times if you have 100 friends is 1/10th. the probability of him showing up 4 times in a row is
.01^4 x .99^6 x 7
1 in 100 of a shot of being there, then to the 4th, because they have to be in a row. then theres 6 spots left (assuming he shows up 4 and only 4 times) out of the 10, but 99 more people, so its 99^6. then x7 because the 4 in a row could take place throughout the first 4, 2-5, 3-6, etc etc. yeah, im really good at probability and all the nPr and nCr shit