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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 9 |
| 8 | 19 |
| 9 | 42 |
| 10 | 149 |
| 11 | 642 |
| 12 | 3217 |
| 13 | 16918 |
| 14 | 103595 |
| 15 | 764774 |
| 16 | 6743975 |
| 17 | 68369223 |
| 18 | 809162389 |
| 19 | 11357687762 |
| 20 | 186710566988 |
| 21 | 3547308633892 |
| 22 | 78610913689329 |
| 23 | 2049663760103557 |
| 24 | 62999437730030008 |
[1,1,1,1,1,3,9,19,42,149,642,3217,16918,103595, 764774,6743975,68369223,809162389,11357687762, 186710566988,3547308633892,78610913689329, 2049663760103557,62999437730030008] |