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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 8 |
| 3 | 38 |
| 4 | 200 |
| 5 | 1112 |
| 6 | 6368 |
| 7 | 37088 |
| 8 | 218240 |
| 9 | 1292672 |
| 10 | 7689728 |
| 11 | 45874688 |
| 12 | 274196480 |
| 13 | 1640978432 |
| 14 | 9829081088 |
| 15 | 58907353088 |
| 16 | 353175633920 |
| 17 | 2117979963392 |
| 18 | 12703584616448 |
| 19 | 76204327436288 |
| 20 | 457157244354560 |
| 21 | 2742668586647552 |
| 22 | 16454912005111808 |
| 23 | 98725073977868288 |
[2,8,38,200,1112,6368,37088,218240,1292672, 7689728,45874688,274196480,1640978432,9829081088, 58907353088,353175633920,2117979963392, 12703584616448,76204327436288,457157244354560, 2742668586647552,16454912005111808, 98725073977868288] |