The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 4 |
| 4 | 4 |
| 5 | 5 |
| 6 | 7 |
| 7 | 8 |
| 8 | 9 |
| 9 | 8 |
| 10 | 9 |
| 11 | 11 |
| 12 | 13 |
| 13 | 11 |
| 14 | 15 |
| 15 | 16 |
| 16 | 14 |
| 17 | 14 |
| 18 | 18 |
| 19 | 20 |
| 20 | 21 |
[2,3,4,4,5,7,8,9,8,9,11,13,11,15,16,14,14,18,20, 21] |