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 | 57 |
| 5 | 285 |
| 6 | 1500 |
| 7 | 8193 |
| 8 | 46011 |
| 9 | 263991 |
| 10 | 1540783 |
| 11 | 9119145 |
| 12 | 54601746 |
| 13 | 330153384 |
| 14 | 2013112923 |
| 15 | 12364421871 |
| 16 | 76425011259 |
| 17 | 475036074345 |
| 18 | 2967394228125 |
| 19 | 18618851162820 |
| 20 | 117291191536701 |
| 21 | 741560529250605 |
| 22 | 4703846060352603 |
| 23 | 29926800398213649 |
| 24 | 190923429145757460 |
[1,1,3,12,57,285,1500,8193,46011,263991,1540783, 9119145,54601746,330153384,2013112923,12364421871, 76425011259,475036074345,2967394228125, 18618851162820,117291191536701,741560529250605, 4703846060352603,29926800398213649, 190923429145757460] |