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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 5 |
| 7 | 15 |
| 8 | 27 |
| 9 | 53 |
| 10 | 153 |
| 11 | 487 |
| 12 | 1719 |
| 13 | 7415 |
| 14 | 32545 |
| 15 | 166197 |
| 16 | 903303 |
| 17 | 5463687 |
| 18 | 37085195 |
| 19 | 288519629 |
| 20 | 2455679981 |
| 21 | 24371430209 |
| 22 | 259645240127 |
| 23 | 3154594586943 |
| 24 | 41721327840785 |
| 25 | 629945561496623 |
[1,1,1,1,1,5,15,27,53,153,487,1719,7415,32545, 166197,903303,5463687,37085195,288519629, 2455679981,24371430209,259645240127,3154594586943, 41721327840785,629945561496623] |