181921
Link
https://school.programmers.co.kr/learn/courses/30/lessons/181919 (opens in a new tab)
Answer
JavaScript
function solution(n, arr = []) {
arr.push(n);
if (n === 1) return arr;
if (n % 2 === 0) return solution(n / 2, arr);
return solution(3 * n + 1, arr);
}