The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 1 |
| 10 | 1 |
| 11 | 1 |
| 12 | 1 |
| 13 | 3 |
| 14 | 3 |
| 15 | 9 |
| 16 | 9 |
| 17 | 23 |
| 18 | 23 |
| 19 | 55 |
| 20 | 55 |
| 21 | 223 |
[1,1,1,1,1,1,1,1,1,1,1,1,3,3,9,9,23,23,55,55,223] |