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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 21 |
| 5 | 106 |
| 6 | 643 |
| 7 | 4547 |
| 8 | 36696 |
| 9 | 332769 |
| 10 | 3349507 |
| 11 | 37054436 |
| 12 | 446867351 |
| 13 | 5834728509 |
| 14 | 82003113550 |
| 15 | 1234297698757 |
| 16 | 19809901558841 |
| 17 | 337707109446702 |
| 18 | 6094059760690035 |
| 19 | 116052543892621951 |
| 20 | 2325905946434516516 |
| 21 | 48937614361477154273 |
| 22 | 1078523843237914046247 |
[1,1,2,5,21,106,643,4547,36696,332769,3349507, 37054436,446867351,5834728509,82003113550, 1234297698757,19809901558841,337707109446702, 6094059760690035,116052543892621951, 2325905946434516516,48937614361477154273, 1078523843237914046247] |