/* Given n>=0, create an array with the pattern * {1, 1, 2, 1, 2, 3, ... 1, 2, 3 .. n} (spaces added to show the * grouping). */ public int[] seriesUp(int n) { int[] arr = new int[n*(n+1)/2]; int index = 0; for(int i = 1; i <= n; i++) { for(int j = 0; j < i; j++) { arr[index + j] = j + 1; } index += i; } return arr; }