The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 33 |
| 6 | 125 |
| 7 | 484 |
| 8 | 1933 |
| 9 | 7883 |
| 10 | 32656 |
| 11 | 137127 |
| 12 | 582353 |
| 13 | 2496711 |
| 14 | 10791823 |
| 15 | 46978411 |
| 16 | 205775845 |
| 17 | 906291623 |
| 18 | 4011033078 |
| 19 | 17829430207 |
| 20 | 79565177628 |
| 21 | 356329040864 |
| 22 | 1600966438342 |
| 23 | 7214304154481 |
| 24 | 32597284112813 |
| 25 | 147655425387293 |
| 26 | 670371400288210 |
[1,0,1,3,9,33,125,484,1933,7883,32656,137127, 582353,2496711,10791823,46978411,205775845, 906291623,4011033078,17829430207,79565177628, 356329040864,1600966438342,7214304154481, 32597284112813,147655425387293,670371400288210] |