The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 43 |
| 5 | 264 |
| 6 | 2804 |
| 7 | 44524 |
| 8 | 1012456 |
| 9 | 30502320 |
| 10 | 1166185222 |
| 11 | 54902972542 |
| 12 | 3115560948081 |
| 13 | 209575881782122 |
| 14 | 16484822517084705 |
| 15 | 1498893370236782629 |
| 16 | 155996155818460127750 |
| 17 | 18424063865105027559797 |
| 18 | 2450806855748517847761175 |
| 19 | 364738110721163795332103692 |
| 20 | 60368334488355648041244493885 |
[1,1,3,9,43,264,2804,44524,1012456,30502320, 1166185222,54902972542,3115560948081, 209575881782122,16484822517084705, 1498893370236782629,155996155818460127750, 18424063865105027559797,2450806855748517847761175, 364738110721163795332103692, 60368334488355648041244493885] |