bilangan yang hilang dalam barisan 1,2,3,6,11,20..... 68 adalah

4, 5, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19.........
Maaf kalau. Salah!

4 , 5, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 39, 31, 32, 33, 34, 35, 36, 37, 38, 39, 49, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67 ..... maaf kalo salah