Definition: You are given a list of integers and an integer target, return a list of a pair of numbers in any order such that they add up to target. If there is no such pair of numbers, then return an empty list
Input: [1, 40, 29, 10, 12, 21, 47, 28, 49, 38, 13, 26, 42, 25, 15, 11, 44, 4, 43, 23], target=16

[1, 15]