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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 84 |
| 5 | 633 |
| 6 | 5730 |
| 7 | 60485 |
| 8 | 729710 |
| 9 | 9904064 |
| 10 | 149358998 |
| 11 | 2477662364 |
| 12 | 44837516675 |
| 13 | 879028693860 |
| 14 | 18558771941586 |
| 15 | 419815668642109 |
| 16 | 10129704474860688 |
| 17 | 259695154154923814 |
| 18 | 7049438079064414206 |
| 19 | 201988316828399901634 |
| 20 | 6092203404985463075656 |
[1,1,3,14,84,633,5730,60485,729710,9904064, 149358998,2477662364,44837516675,879028693860, 18558771941586,419815668642109,10129704474860688, 259695154154923814,7049438079064414206, 201988316828399901634,6092203404985463075656] |