The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 13 |
| 6 | 38 |
| 7 | 125 |
| 8 | 449 |
| 9 | 1742 |
| 10 | 7269 |
| 11 | 32433 |
| 12 | 153850 |
| 13 | 772397 |
| 14 | 4088773 |
| 15 | 22746858 |
| 16 | 132601933 |
| 17 | 807880821 |
| 18 | 5132235182 |
| 19 | 33925263901 |
| 20 | 232905588441 |
| 21 | 1657807491222 |
| 22 | 12215424018837 |
| 23 | 93042845392105 |
| 24 | 731622663432978 |
| 25 | 5931915237693517 |
| 26 | 49535826242154973 |
[1,1,1,2,5,13,38,125,449,1742,7269,32433,153850, 772397,4088773,22746858,132601933,807880821, 5132235182,33925263901,232905588441,1657807491222, 12215424018837,93042845392105,731622663432978, 5931915237693517,49535826242154973] |