freeCodeCamp Challenge Guide: Problem 76: Counting summations

Guide
#1

Problem 76: Counting summations

Solutions

Solution 1 (Click to Show/Hide) 
function countingSummations(n) {
  const combinations = new Array(n + 1).fill(0);
  combinations[0] = 1;

  for (let i = 1; i < n; i++) {
    for (let j = i; j < n + 1; j++) {
      combinations[j] += combinations[j - i];
    }
  }
  return combinations[n];
}