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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 45 |
| 5 | 197 |
| 6 | 903 |
| 7 | 4278 |
| 8 | 20788 |
| 9 | 103050 |
| 10 | 519268 |
| 11 | 2653278 |
| 12 | 13725388 |
[1,3,11,45,197,903,4278,20788,103050,519268, 2653278,13725388] |