The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 59 |
| 5 | 266 |
| 6 | 1203 |
| 7 | 5489 |
| 8 | 25259 |
| 9 | 117022 |
| 10 | 545038 |
| 11 | 2549592 |
| 12 | 11970035 |
| 13 | 56372460 |
| 14 | 266194295 |
| 15 | 1259910113 |
| 16 | 5975382699 |
| 17 | 28390616727 |
| 18 | 135108035502 |
| 19 | 643891031826 |
| 20 | 3072604703774 |
| 21 | 14679493913048 |
| 22 | 70206875750168 |
| 23 | 336103001918788 |
| 24 | 1610476039036259 |
| 25 | 7723148579525441 |
[1,1,3,13,59,266,1203,5489,25259,117022,545038, 2549592,11970035,56372460,266194295,1259910113, 5975382699,28390616727,135108035502,643891031826, 3072604703774,14679493913048,70206875750168, 336103001918788,1610476039036259,7723148579525441] |