The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 9 |
| 5 | 16 |
| 6 | 14 |
| 7 | 52 |
| 8 | 148 |
| 9 | 251 |
| 10 | 565 |
| 11 | 1499 |
| 12 | 3243 |
| 13 | 7060 |
| 14 | 16908 |
| 15 | 38770 |
| 16 | 86560 |
| 17 | 199485 |
| 18 | 459507 |
| 19 | 1042743 |
| 20 | 2381573 |
| 21 | 5463922 |
| 22 | 12473396 |
| 23 | 28472588 |
| 24 | 65151034 |
| 25 | 148934761 |
| 26 | 340205233 |
| 27 | 777721477 |
| 28 | 1777971169 |
| 29 | 4063085580 |
[0,1,1,1,9,16,14,52,148,251,565,1499,3243,7060, 16908,38770,86560,199485,459507,1042743,2381573, 5463922,12473396,28472588,65151034,148934761, 340205233,777721477,1777971169,4063085580] |