The sequence provided is: 1, 2, 3, 7, 11, 16, , 29. To find the missing number, we *yze the differences between consecutive terms:

1. Differences between terms:
2
1 = 1
3
2 = 1
7
3 = 4
11
7 = 4
16
11 = 5
The next difference is 5 (following a pattern of repeating differences twice), leading to 16 + 5 = 21.
Finally, 29
21 = 8, confirming the next difference is 8.
2. Pattern in differences:
The differences 1, 1, 4, 4, 5, 5, 8 show that each difference is repeated twice, with increments of +3, +1, +3 between the distinct values (1 → 4 → 5 → 8).
3. Verification:
Following the pattern, after 16, adding 5 gives 21, and adding 8 to 21 results in 29, which matches the last term.
Answer: boxed{21}