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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 16 |
| 4 | 152 |
| 5 | 1449 |
| 6 | 11655 |
| 7 | 89469 |
| 8 | 705803 |
| 9 | 5771383 |
| 10 | 45213223 |
| 11 | 344221421 |
| 12 | 2576621623 |
| 13 | 19476715122 |
| 14 | 147713174987 |
| 15 | 1110131277687 |
| 16 | 8315461638940 |
| 17 | 62491630903612 |
| 18 | 470960349189386 |
| 19 | 3550021202822759 |
| 20 | 26747955424745122 |
[1,2,16,152,1449,11655,89469,705803,5771383, 45213223,344221421,2576621623,19476715122, 147713174987,1110131277687,8315461638940, 62491630903612,470960349189386,3550021202822759, 26747955424745122] |