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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 18 |
| 5 | 52 |
| 6 | 184 |
| 7 | 688 |
| 8 | 2512 |
| 9 | 8864 |
| 10 | 30784 |
| 11 | 107648 |
| 12 | 384432 |
| 13 | 1403872 |
| 14 | 5205568 |
| 15 | 19443328 |
| 16 | 72817856 |
| 17 | 273199488 |
| 18 | 1027939072 |
| 19 | 3883718144 |
| 20 | 14741042464 |
| 21 | 56189409088 |
| 22 | 214931447680 |
| 23 | 824443822848 |
| 24 | 3169934397184 |
| 25 | 12214858010112 |
| 26 | 47168251137024 |
[1,2,4,8,18,52,184,688,2512,8864,30784,107648, 384432,1403872,5205568,19443328,72817856, 273199488,1027939072,3883718144,14741042464, 56189409088,214931447680,824443822848, 3169934397184,12214858010112,47168251137024] |