The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 65 |
| 5 | 384 |
| 6 | 2197 |
| 7 | 14078 |
| 8 | 94739 |
| 9 | 670612 |
| 10 | 4899280 |
| 11 | 36645899 |
| 12 | 281037158 |
| 13 | 2197679518 |
| 14 | 17489660228 |
| 15 | 141241307806 |
| 16 | 1155345218645 |
| 17 | 9559672712389 |
| 18 | 79905432682918 |
| 19 | 674005489358155 |
| 20 | 5731854529045978 |
| 21 | 49105864505432392 |
| 22 | 423531623342726441 |
[1,1,3,12,65,384,2197,14078,94739,670612,4899280, 36645899,281037158,2197679518,17489660228, 141241307806,1155345218645,9559672712389, 79905432682918,674005489358155,5731854529045978, 49105864505432392,423531623342726441] |