The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 27 |
| 3 | 155 |
| 4 | 924 |
| 5 | 5643 |
| 6 | 35036 |
| 7 | 220133 |
| 8 | 1395549 |
| 9 | 8909120 |
| 10 | 57193916 |
| 11 | 368849781 |
| 12 | 2387828041 |
| 13 | 15507998588 |
| 14 | 100996781823 |
| 15 | 659323123227 |
| 16 | 4313184213360 |
| 17 | 28268290229481 |
| 18 | 185572527135506 |
| 19 | 1220015370938720 |
| 20 | 8031387080176074 |
| 21 | 52934002548821884 |
| 22 | 349261397277490615 |
[1,5,27,155,924,5643,35036,220133,1395549,8909120, 57193916,368849781,2387828041,15507998588, 100996781823,659323123227,4313184213360, 28268290229481,185572527135506,1220015370938720, 8031387080176074,52934002548821884, 349261397277490615] |