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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 30 |
| 5 | 117 |
| 6 | 533 |
| 7 | 2599 |
| 8 | 13919 |
| 9 | 79620 |
| 10 | 487810 |
| 11 | 3167265 |
| 12 | 21744187 |
| 13 | 157020697 |
| 14 | 1189321019 |
| 15 | 9417789650 |
| 16 | 77774264012 |
| 17 | 668233623419 |
| 18 | 5961395449795 |
| 19 | 55117233908411 |
| 20 | 527263186773227 |
| 21 | 5210880621612366 |
| 22 | 53130216638022540 |
| 23 | 558176360466846439 |
[1,1,3,8,30,117,533,2599,13919,79620,487810, 3167265,21744187,157020697,1189321019,9417789650, 77774264012,668233623419,5961395449795, 55117233908411,527263186773227,5210880621612366, 53130216638022540,558176360466846439] |