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 | 81 |
| 5 | 669 |
| 6 | 6955 |
| 7 | 88505 |
| 8 | 1346209 |
| 9 | 23998521 |
| 10 | 493956467 |
| 11 | 11596542533 |
| 12 | 307301505073 |
| 13 | 9110471500693 |
| 14 | 299893197116059 |
| 15 | 10888674034993905 |
| 16 | 433549376981078593 |
| 17 | 18833037527449398129 |
| 18 | 888439543634687700579 |
[1,1,3,13,81,669,6955,88505,1346209,23998521, 493956467,11596542533,307301505073,9110471500693, 299893197116059,10888674034993905, 433549376981078593,18833037527449398129, 888439543634687700579] |