The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 106 |
| 5 | 851 |
| 6 | 8044 |
| 7 | 87540 |
| 8 | 1078177 |
| 9 | 14827510 |
| 10 | 225228130 |
| 11 | 3745187549 |
| 12 | 67666969438 |
| 13 | 1320018345504 |
| 14 | 27651573264631 |
| 15 | 619077538462468 |
| 16 | 14752261527199414 |
| 17 | 372797929345665683 |
| 18 | 9958134039336196072 |
| 19 | 280354873141108774272 |
| 20 | 8297089960595144115505 |
| 21 | 257514010200875255884522 |
[1,3,16,106,851,8044,87540,1078177,14827510, 225228130,3745187549,67666969438,1320018345504, 27651573264631,619077538462468,14752261527199414, 372797929345665683,9958134039336196072, 280354873141108774272,8297089960595144115505, 257514010200875255884522] |