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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 113 |
| 5 | 955 |
| 6 | 9178 |
| 7 | 97427 |
| 8 | 1121705 |
| 9 | 13836694 |
| 10 | 181295019 |
| 11 | 2507119320 |
| 12 | 36416096984 |
| 13 | 553461581406 |
| 14 | 8774534872463 |
| 15 | 144744539399484 |
| 16 | 2479088917439527 |
| 17 | 44004108702467428 |
| 18 | 808171916050540308 |
| 19 | 15335535608825061803 |
| 20 | 300272362335527090277 |
| 21 | 6059534345675248667550 |
[1,1,3,16,113,955,9178,97427,1121705,13836694, 181295019,2507119320,36416096984,553461581406, 8774534872463,144744539399484,2479088917439527, 44004108702467428,808171916050540308, 15335535608825061803,300272362335527090277, 6059534345675248667550] |