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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 17 |
| 5 | 57 |
| 6 | 337 |
| 7 | 1661 |
| 8 | 9697 |
| 9 | 68529 |
| 10 | 451809 |
| 11 | 3570613 |
| 12 | 29324913 |
| 13 | 247557481 |
| 14 | 2348275633 |
| 15 | 22399292077 |
| 16 | 229227939521 |
| 17 | 2476740370529 |
| 18 | 27378158737089 |
| 19 | 323000223133285 |
| 20 | 3912000089144273 |
| 21 | 49350756905258905 |
| 22 | 649905519911431953 |
| 23 | 8776449485870211549 |
[1,1,1,5,17,57,337,1661,9697,68529,451809,3570613, 29324913,247557481,2348275633,22399292077, 229227939521,2476740370529,27378158737089, 323000223133285,3912000089144273, 49350756905258905,649905519911431953, 8776449485870211549] |