# 2014 AMC 12B Problems/Problem 23

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## Problem

The number 2017 is prime. Let . What is the remainder when is divided by 2017?

## Solution

Note that . We have for Therefore This is simply an alternating series of triangular numbers that goes like this: After finding the first few sums of the series, it becomes apparent that and Obviously, falls in the second category, so our desired value is

(Solution by kevin38017)