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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 3 |
| 8 | 9 |
| 9 | 19 |
| 10 | 61 |
| 11 | 211 |
| 12 | 741 |
| 13 | 3813 |
| 14 | 22505 |
| 15 | 147447 |
| 16 | 1175399 |
| 17 | 10583799 |
| 18 | 109540847 |
| 19 | 1364336983 |
| 20 | 19785643957 |
| 21 | 336137809321 |
| 22 | 6744593577357 |
| 23 | 157257981066897 |
[1,1,1,1,1,1,3,9,19,61,211,741,3813,22505,147447, 1175399,10583799,109540847,1364336983,19785643957, 336137809321,6744593577357,157257981066897] |