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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 53 |
| 4 | 242 |
| 5 | 1138 |
| 6 | 5434 |
| 7 | 26199 |
| 8 | 127376 |
| 9 | 622268 |
| 10 | 3053438 |
| 11 | 15029014 |
| 12 | 74157258 |
| 13 | 366653302 |
| 14 | 1815673654 |
| 15 | 9003329553 |
| 16 | 44692323636 |
| 17 | 222054482004 |
| 18 | 1104120942040 |
| 19 | 5493564170090 |
| 20 | 27348418661820 |
| 21 | 136212033035508 |
| 22 | 678698740724990 |
| 23 | 3382928052071028 |
| 24 | 16867212596433914 |
| 25 | 84122447519298902 |
[1,3,12,53,242,1138,5434,26199,127376,622268, 3053438,15029014,74157258,366653302,1815673654, 9003329553,44692323636,222054482004,1104120942040, 5493564170090,27348418661820,136212033035508, 678698740724990,3382928052071028, 16867212596433914,84122447519298902] |