The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 13 |
| 4 | 73 |
| 5 | 281 |
| 6 | 1741 |
| 7 | 8485 |
| 8 | 57233 |
| 9 | 328753 |
| 10 | 2389141 |
| 11 | 15539261 |
| 12 | 120661465 |
| 13 | 866545993 |
| 14 | 7140942173 |
| 15 | 55667517781 |
| 16 | 484124048161 |
| 17 | 4046845186145 |
| 18 | 36967280461093 |
| 19 | 328340133863533 |
| 20 | 3137853448906601 |
| 21 | 29405064157989241 |
[1,1,5,13,73,281,1741,8485,57233,328753,2389141, 15539261,120661465,866545993,7140942173, 55667517781,484124048161,4046845186145, 36967280461093,328340133863533,3137853448906601, 29405064157989241] |