The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 41 |
| 3 | 139 |
| 4 | 385 |
| 5 | 3175 |
| 6 | 14940 |
| 7 | 58901 |
| 8 | 325922 |
| 9 | 1616869 |
| 10 | 7303419 |
| 11 | 36440971 |
| 12 | 179690470 |
| 13 | 852213260 |
| 14 | 4150469302 |
| 15 | 20279868193 |
| 16 | 97720833639 |
| 17 | 473767953000 |
| 18 | 2303837003374 |
| 19 | 11153405540217 |
| 20 | 54053378441391 |
| 21 | 262342164214663 |
| 22 | 1271623035196752 |
[1,41,139,385,3175,14940,58901,325922,1616869, 7303419,36440971,179690470,852213260,4150469302, 20279868193,97720833639,473767953000, 2303837003374,11153405540217,54053378441391, 262342164214663,1271623035196752] |