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| n | a(n) |
|---|---|
| 1 | 256 |
| 2 | 1876 |
| 3 | 13924 |
| 4 | 103264 |
| 5 | 769680 |
| 6 | 5705156 |
| 7 | 42501300 |
| 8 | 315065200 |
| 9 | 2347267424 |
| 10 | 17400203636 |
| 11 | 129631996580 |
| 12 | 960959725312 |
| 13 | 7159191300272 |
| 14 | 53070925060004 |
| 15 | 395380448791316 |
| 16 | 2930946979641872 |
| 17 | 21835672557183872 |
| 18 | 161867373265982548 |
[256,1876,13924,103264,769680,5705156,42501300, 315065200,2347267424,17400203636,129631996580, 960959725312,7159191300272,53070925060004, 395380448791316,2930946979641872, 21835672557183872,161867373265982548] |