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2018 PUMaC Algebra A2

Source:

November 25, 2018
PuMACalgebra

Problem Statement

If a1,a2,a_1, a_2, \ldots is a sequence of real numbers such that for all nn, k=1nak(kn)2=1,\sum_{k = 1}^n a_k \left( \frac{k}{n} \right)^2 = 1, find the smallest nn such that an<12018a_n < \frac{1}{2018}.