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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 33 |
| 5 | 136 |
| 6 | 723 |
| 7 | 3968 |
| 8 | 25953 |
| 9 | 176896 |
| 10 | 1376643 |
| 11 | 11184128 |
| 12 | 101031873 |
| 13 | 951878656 |
| 14 | 9795436563 |
| 15 | 104932671488 |
| 16 | 1212135593793 |
| 17 | 14544442556416 |
| 18 | 186388033956483 |
| 19 | 2475749026562048 |
| 20 | 34859622790687713 |
| 21 | 507711943253426176 |
| 22 | 7791941518975112403 |
| 23 | 123460740095103991808 |
[1,1,3,8,33,136,723,3968,25953,176896,1376643, 11184128,101031873,951878656,9795436563, 104932671488,1212135593793,14544442556416, 186388033956483,2475749026562048, 34859622790687713,507711943253426176, 7791941518975112403,123460740095103991808] |