The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 2 |
| 5 | 3 |
| 6 | 3 |
| 7 | 4 |
| 8 | 4 |
| 9 | 4 |
| 10 | 4 |
| 11 | 4 |
| 12 | 4 |
| 13 | 4 |
| 14 | 4 |
| 15 | 4 |
| 16 | 4 |
| 17 | 5 |
| 18 | 5 |
| 19 | 5 |
| 20 | 5 |
[0,1,2,2,2,3,3,4,4,4,4,4,4,4,4,4,4,5,5,5,5] |