The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 37 |
| 3 | 428 |
| 4 | 3164 |
| 5 | 18945 |
| 6 | 102501 |
| 7 | 529312 |
| 8 | 2679328 |
| 9 | 13455689 |
| 10 | 67378445 |
| 11 | 337053276 |
| 12 | 1685515212 |
| 13 | 8427947353 |
| 14 | 42140274589 |
| 15 | 210702132320 |
| 16 | 1053511710176 |
| 17 | 5267559970737 |
| 18 | 26337801743253 |
| 19 | 131689011192364 |
| 20 | 658445059161820 |
[0,1,37,428,3164,18945,102501,529312,2679328, 13455689,67378445,337053276,1685515212,8427947353, 42140274589,210702132320,1053511710176, 5267559970737,26337801743253,131689011192364, 658445059161820] |