The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 19 |
| 6 | 72 |
| 7 | 280 |
| 8 | 1348 |
| 9 | 7542 |
| 10 | 48290 |
| 11 | 348902 |
| 12 | 2805666 |
| 13 | 24797845 |
| 14 | 238678891 |
| 15 | 2482575930 |
| 16 | 27731295522 |
| 17 | 330955304428 |
| 18 | 4201424981020 |
| 19 | 56521276891669 |
| 20 | 803122164193328 |
| 21 | 12018137424023094 |
| 22 | 188906053776728602 |
| 23 | 3111632374404898304 |
| 24 | 53597059526977558291 |
[0,1,3,7,19,72,280,1348,7542,48290,348902,2805666, 24797845,238678891,2482575930,27731295522, 330955304428,4201424981020,56521276891669, 803122164193328,12018137424023094, 188906053776728602,3111632374404898304, 53597059526977558291] |