Just for fun

Revision en1, by zzzz-, 2019-05-14 05:20:06

We all know what a permutation is. So, I remember a good problem from school. Let P be a permutation of 1, 2, 3, .... n. We define the function f(P) as the number of positions where P[i] = i (also known as fixed points I think). What is the expect value of f :)

Tags #combinatorics, #number theory, #math


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en1 English zzzz- 2019-05-14 05:20:06 277 Initial revision (published)