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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 65 |
| 6 | 355 |
| 7 | 2051 |
| 8 | 12329 |
| 9 | 76317 |
| 10 | 483191 |
| 11 | 3114551 |
| 12 | 20370173 |
| 13 | 134844697 |
| 14 | 901750067 |
| 15 | 6082836811 |
| 16 | 41340928785 |
| 17 | 282808887861 |
| 18 | 1945826116687 |
| 19 | 13456445362911 |
| 20 | 93483434517701 |
[1,1,3,13,65,355,2051,12329,76317,483191,3114551, 20370173,134844697,901750067,6082836811, 41340928785,282808887861,1945826116687, 13456445362911,93483434517701] |