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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 35 |
| 4 | 161 |
| 5 | 768 |
| 6 | 3773 |
| 7 | 19006 |
| 8 | 97840 |
| 9 | 513264 |
| 10 | 2737121 |
| 11 | 14805805 |
| 12 | 81082383 |
| 13 | 448805300 |
| 14 | 2507310567 |
| 15 | 14120503129 |
| 16 | 80082573017 |
| 17 | 456977964520 |
| 18 | 2621830478785 |
| 19 | 15114658956625 |
| 20 | 87508451311125 |
| 21 | 508589225952740 |
| 22 | 2966098696204660 |
[1,2,8,35,161,768,3773,19006,97840,513264,2737121, 14805805,81082383,448805300,2507310567, 14120503129,80082573017,456977964520, 2621830478785,15114658956625,87508451311125, 508589225952740,2966098696204660] |