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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 52 |
| 6 | 208 |
| 7 | 676 |
| 8 | 2208 |
| 9 | 7696 |
| 10 | 25508 |
| 11 | 83880 |
| 12 | 283660 |
| 13 | 948060 |
| 14 | 3148584 |
| 15 | 10557340 |
| 16 | 35322344 |
| 17 | 117782000 |
| 18 | 393897360 |
| 19 | 1317263556 |
| 20 | 4398977356 |
| 21 | 14702092412 |
| 22 | 49147888808 |
| 23 | 164212896136 |
| 24 | 548766913936 |
| 25 | 1834139828140 |
| 26 | 6129193479188 |
[1,2,6,16,52,208,676,2208,7696,25508,83880,283660, 948060,3148584,10557340,35322344,117782000, 393897360,1317263556,4398977356,14702092412, 49147888808,164212896136,548766913936, 1834139828140,6129193479188] |