The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 14 |
| 2 | 154 |
| 3 | 1442 |
| 4 | 12306 |
| 5 | 98448 |
| 6 | 751338 |
| 7 | 5530800 |
| 8 | 39567066 |
| 9 | 276569216 |
| 10 | 1896366472 |
| 11 | 12793873820 |
| 12 | 85126910050 |
| 13 | 559668331068 |
| 14 | 3641262380472 |
| 15 | 23473114767228 |
| 16 | 150084462238410 |
| 17 | 952629409818492 |
| 18 | 6006967242402280 |
| 19 | 37653314869948316 |
| 20 | 234749051092791928 |
| 21 | 1456337836252645280 |
[1,14,154,1442,12306,98448,751338,5530800, 39567066,276569216,1896366472,12793873820, 85126910050,559668331068,3641262380472, 23473114767228,150084462238410,952629409818492, 6006967242402280,37653314869948316, 234749051092791928,1456337836252645280] |