The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 5 |
| 7 | 10 |
| 8 | 17 |
| 9 | 27 |
| 10 | 68 |
| 11 | 107 |
| 12 | 217 |
| 13 | 420 |
| 14 | 884 |
| 15 | 1761 |
| 16 | 3679 |
| 17 | 7469 |
| 18 | 15437 |
| 19 | 31396 |
| 20 | 64369 |
[1,0,0,0,0,2,5,10,17,27,68,107,217,420,884,1761, 3679,7469,15437,31396,64369] |