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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 32 |
| 5 | 112 |
| 6 | 431 |
| 7 | 1678 |
| 8 | 6763 |
| 9 | 27670 |
| 10 | 115426 |
| 11 | 487077 |
| 12 | 2082049 |
| 13 | 8977804 |
| 14 | 39046114 |
| 15 | 171030912 |
| 16 | 753916676 |
| 17 | 3341768584 |
| 18 | 14885951812 |
| 19 | 66601109529 |
| 20 | 299166820070 |
| 21 | 1348655444107 |
| 22 | 6099540897124 |
| 23 | 27668136578751 |
| 24 | 125845441835454 |
| 25 | 573819151893002 |
| 26 | 2622450568940290 |
| 27 | 12010412791891348 |
| 28 | 55113705601828460 |
[1,1,3,9,32,112,431,1678,6763,27670,115426,487077, 2082049,8977804,39046114,171030912,753916676, 3341768584,14885951812,66601109529,299166820070, 1348655444107,6099540897124,27668136578751, 125845441835454,573819151893002,2622450568940290, 12010412791891348,55113705601828460] |