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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 3 |
| 9 | 9 |
| 10 | 19 |
| 11 | 43 |
| 12 | 141 |
| 13 | 419 |
| 14 | 1255 |
| 15 | 5087 |
| 16 | 24913 |
| 17 | 131971 |
| 18 | 734375 |
| 19 | 4818949 |
| 20 | 34664741 |
| 21 | 269727721 |
| 22 | 2371934855 |
| 23 | 24159321229 |
| 24 | 274622983853 |
[1,1,1,1,1,1,1,3,9,19,43,141,419,1255,5087,24913, 131971,734375,4818949,34664741,269727721, 2371934855,24159321229,274622983853] |