2015 UMO Problems/Problem 3

Problem

Find, with proof, all positive integers $n$ with $2\le n\le 20$ such that the greatest common divisor of the coefficients of $(x+y)^n-x^n-y^n$ is equal to exactly $3$.


Solution

See Also

2015 UMO (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
1 2 3 4 5 6
All UMO Problems and Solutions

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