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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 48 |
| 5 | 158 |
| 6 | 532 |
| 7 | 1778 |
| 8 | 5952 |
| 9 | 19922 |
| 10 | 66676 |
| 11 | 223166 |
| 12 | 746928 |
| 13 | 2499950 |
| 14 | 8367268 |
| 15 | 28005026 |
| 16 | 93732096 |
| 17 | 313718882 |
| 18 | 1050008932 |
| 19 | 3514352558 |
| 20 | 11762446512 |
| 21 | 39368602238 |
| 22 | 131765686708 |
| 23 | 441016322834 |
| 24 | 1476070150464 |
| 25 | 4940368363442 |
[1,2,4,14,48,158,532,1778,5952,19922,66676,223166, 746928,2499950,8367268,28005026,93732096, 313718882,1050008932,3514352558,11762446512, 39368602238,131765686708,441016322834, 1476070150464,4940368363442] |