The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 19 |
| 3 | 138 |
| 4 | 1059 |
| 5 | 8378 |
| 6 | 67582 |
| 7 | 552576 |
| 8 | 4563235 |
| 9 | 37972290 |
| 10 | 317894394 |
| 11 | 2674398268 |
| 12 | 22590697614 |
| 13 | 191475925332 |
| 14 | 1627653567916 |
| 15 | 13870754053388 |
| 16 | 118464647799075 |
| 17 | 1013709715774130 |
| 18 | 8689197042438274 |
| 19 | 74594573994750972 |
| 20 | 641252293546113434 |
| 21 | 5519339268476249676 |
| 22 | 47558930664216470628 |
[1,3,19,138,1059,8378,67582,552576,4563235, 37972290,317894394,2674398268,22590697614, 191475925332,1627653567916,13870754053388, 118464647799075,1013709715774130,8689197042438274, 74594573994750972,641252293546113434, 5519339268476249676,47558930664216470628] |