@firanurrahma
n = 1 {1} n = 2 {1,2,1} n = 3 {1,2,1,3,1,2,1} n = 4 {1,2,1,3,1,2,1,4,1,2,1,3,1,2,1} angka 1 selalu berada pada indeks ke-20 = 1, 3, 5, 7, 9, 11, 13, 1...