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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 21 |
| 3 | 93 |
| 4 | 409 |
| 5 | 1837 |
| 6 | 8209 |
| 7 | 36969 |
| 8 | 166041 |
| 9 | 748889 |
| 10 | 3373941 |
| 11 | 15248153 |
| 12 | 68840633 |
[1,5,21,93,409,1837,8209,36969,166041,748889, 3373941,15248153,68840633] |