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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 31 |
| 5 | 103 |
| 6 | 394 |
| 7 | 1491 |
| 8 | 6000 |
| 9 | 23753 |
| 10 | 97516 |
| 11 | 403991 |
| 12 | 1695218 |
| 13 | 7143447 |
| 14 | 30524744 |
| 15 | 131270682 |
| 16 | 567335019 |
| 17 | 2466465890 |
| 18 | 10796808479 |
| 19 | 47437462779 |
| 20 | 209184240720 |
| 21 | 926697463398 |
| 22 | 4120918498155 |
| 23 | 18372504785492 |
| 24 | 82161414755245 |
| 25 | 368598197247809 |
| 26 | 1657561967984505 |
| 27 | 7469751629688210 |
| 28 | 33744411861731459 |
[1,1,3,8,31,103,394,1491,6000,23753,97516,403991, 1695218,7143447,30524744,131270682,567335019, 2466465890,10796808479,47437462779,209184240720, 926697463398,4120918498155,18372504785492, 82161414755245,368598197247809,1657561967984505, 7469751629688210,33744411861731459] |