The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 13 |
| 5 | 25 |
| 6 | 65 |
| 7 | 181 |
| 8 | 445 |
| 9 | 1113 |
| 10 | 2945 |
| 11 | 7685 |
| 12 | 19821 |
| 13 | 51865 |
| 14 | 136513 |
| 15 | 358229 |
| 16 | 942109 |
| 17 | 2487385 |
| 18 | 6573825 |
| 19 | 17387045 |
| 20 | 46066253 |
| 21 | 122213913 |
| 22 | 324512833 |
| 23 | 862511605 |
| 24 | 2294698109 |
| 25 | 6109933657 |
| 26 | 16280439937 |
| 27 | 43411979845 |
| 28 | 115835462445 |
[1,1,1,5,13,25,65,181,445,1113,2945,7685,19821, 51865,136513,358229,942109,2487385,6573825, 17387045,46066253,122213913,324512833,862511605, 2294698109,6109933657,16280439937,43411979845, 115835462445] |