The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 38 |
| 5 | 241 |
| 6 | 1586 |
| 7 | 10519 |
| 8 | 69878 |
| 9 | 464353 |
| 10 | 3085922 |
| 11 | 20508199 |
| 12 | 136292294 |
| 13 | 905764561 |
| 14 | 6019485842 |
| 15 | 40004005687 |
| 16 | 265856672918 |
| 17 | 1766817332161 |
| 18 | 11741828601026 |
| 19 | 78033272818759 |
| 20 | 518589725140838 |
| 21 | 3446418345757873 |
| 22 | 22904039239795442 |
| 23 | 152214548806542679 |
| 24 | 1011580037294182454 |
| 25 | 6722709359094575521 |
[1,1,2,7,38,241,1586,10519,69878,464353,3085922, 20508199,136292294,905764561,6019485842, 40004005687,265856672918,1766817332161, 11741828601026,78033272818759,518589725140838, 3446418345757873,22904039239795442, 152214548806542679,1011580037294182454, 6722709359094575521] |