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2001 IMO Shortlist Problems/C5

Problem

Find all finite sequences $(x_0, x_1, \ldots,x_n)$ such that for every $j$, $0 \leq j \leq n$, $x_j$ equals the number of times $j$ appears in the sequence.

Solution

See Problem 23, Chapter 4, in 102 Combinatorial Problems by Andreescu and Feng.

Resources

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