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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 54 |
| 3 | 366 |
| 4 | 2482 |
| 5 | 16834 |
| 6 | 114178 |
| 7 | 774426 |
| 8 | 5252642 |
| 9 | 35626714 |
| 10 | 241642738 |
| 11 | 1638972746 |
| 12 | 11116542082 |
| 13 | 75399367194 |
| 14 | 511405842898 |
| 15 | 3468675479466 |
| 16 | 23526734684322 |
| 17 | 159573084361274 |
| 18 | 1082324835734258 |
| 19 | 7341006503296586 |
| 20 | 49791314679463362 |
| 21 | 337715954398900954 |
[1,8,54,366,2482,16834,114178,774426,5252642, 35626714,241642738,1638972746,11116542082, 75399367194,511405842898,3468675479466, 23526734684322,159573084361274,1082324835734258, 7341006503296586,49791314679463362, 337715954398900954] |