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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 63 |
| 5 | 324 |
| 6 | 1736 |
| 7 | 9589 |
| 8 | 54223 |
| 9 | 312369 |
| 10 | 1826847 |
| 11 | 10818156 |
| 12 | 64737684 |
| 13 | 390877456 |
| 14 | 2378312780 |
| 15 | 14568360645 |
| 16 | 89766137967 |
| 17 | 556008951667 |
| 18 | 3459976045201 |
| 19 | 21621154097573 |
| 20 | 135619427912599 |
| 21 | 853590782088272 |
| 22 | 5389272616262656 |
| 23 | 34123058549079788 |
| 24 | 216621704634708868 |
[1,1,3,13,63,324,1736,9589,54223,312369,1826847, 10818156,64737684,390877456,2378312780, 14568360645,89766137967,556008951667, 3459976045201,21621154097573,135619427912599, 853590782088272,5389272616262656, 34123058549079788,216621704634708868] |