MathDB
Simple Summation Problem

Source:

August 11, 2019
Summation

Problem Statement

Each of the numbers x1,x2,…,x101x_1, x_2, \ldots, x_{101} is ±1\pm 1. What is the smallest positive value of ∑1≤i<j≤101xixj\sum_{1\leq i < j \leq 101} x_i x_j ?
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