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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 5 |
| 8 | 13 |
| 9 | 29 |
| 10 | 115 |
| 11 | 371 |
| 12 | 1127 |
| 13 | 6493 |
| 14 | 42101 |
| 15 | 265099 |
| 16 | 2205911 |
| 17 | 20203737 |
| 18 | 188160663 |
| 19 | 2232930361 |
| 20 | 31949821401 |
| 21 | 512095816829 |
| 22 | 9852484817887 |
| 23 | 220067190717237 |
[1,1,1,1,1,1,5,13,29,115,371,1127,6493,42101, 265099,2205911,20203737,188160663,2232930361, 31949821401,512095816829,9852484817887, 220067190717237] |