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2021 AMC 10D Question 22

AMC10 · 2021 AMC 10D

Question 22

For each integer $n\ge2,$ let $S_n$ be the sum of all products $jk,$ where $j$ and $k$ are integers and $1\le j<k\le n.$ What is the sum of the $10$ least values of $n$ such that $S_n$ is divisible by $3?$
  1. $ \ 196 $
  2. $ \ 197 $
  3. $ \ 198 $
  4. $ \ 199 $
  5. $ \ 200 $