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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 36 |
| 3 | 94 |
| 4 | 278 |
| 5 | 1062 |
| 6 | 3650 |
| 7 | 11856 |
| 8 | 39444 |
| 9 | 135704 |
| 10 | 456980 |
| 11 | 1534668 |
| 12 | 5166204 |
| 13 | 17480600 |
| 14 | 58888528 |
| 15 | 198548648 |
| 16 | 669291696 |
| 17 | 2258436248 |
| 18 | 7613387344 |
| 19 | 25676313144 |
| 20 | 86575342536 |
| 21 | 291991130840 |
| 22 | 984557555352 |
| 23 | 3320284572360 |
| 24 | 11196209499736 |
| 25 | 37757232570616 |
[1,8,36,94,278,1062,3650,11856,39444,135704, 456980,1534668,5166204,17480600,58888528, 198548648,669291696,2258436248,7613387344, 25676313144,86575342536,291991130840,984557555352, 3320284572360,11196209499736,37757232570616] |