The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 56 |
| 3 | 520 |
| 4 | 4832 |
| 5 | 44896 |
| 6 | 417152 |
| 7 | 3875968 |
| 8 | 36013568 |
| 9 | 334620160 |
| 10 | 3109124096 |
| 11 | 28888434688 |
| 12 | 268416966656 |
| 13 | 2493996949504 |
| 14 | 23172979195904 |
| 15 | 215311796961280 |
| 16 | 2000570126041088 |
| 17 | 18588302571864064 |
| 18 | 172713262087405568 |
[6,56,520,4832,44896,417152,3875968,36013568, 334620160,3109124096,28888434688,268416966656, 2493996949504,23172979195904,215311796961280, 2000570126041088,18588302571864064, 172713262087405568] |