The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 3 |
| 7 | 4 |
| 8 | 5 |
| 9 | 6 |
| 10 | 7 |
| 11 | 10 |
| 12 | 13 |
| 13 | 17 |
| 14 | 21 |
| 15 | 28 |
| 16 | 53 |
| 17 | 107 |
| 18 | 211 |
| 19 | 370 |
| 20 | 746 |
| 21 | 31957632 |
[1,1,1,2,3,4,5,6,7,10,13,17,21,28,53,107,211,370, 746,31957632] |