MathDB
Putnam 1958 November B7

Source: Putnam 1958 November

July 19, 2022
PutnampermutationsAverage

Problem Statement

Let a1,a2,…,ana_1 ,a_2 ,\ldots, a_n be a permutation of the integers 1,2,…,n.1,2,\ldots, n. Call aia_i a big integer if ai>aja_i >a_j for all i<j.i<j. Find the mean number of big integers over all permutations on the first nn postive integers.
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