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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 17 |
| 4 | 83 |
| 5 | 461 |
| 6 | 2873 |
| 7 | 19846 |
| 8 | 150418 |
| 9 | 1240398 |
| 10 | 11051017 |
| 11 | 105740309 |
| 12 | 1081101474 |
| 13 | 11758967146 |
| 14 | 135544030566 |
| 15 | 1650178088102 |
| 16 | 21155166649234 |
| 17 | 284821038726404 |
| 18 | 4017445572746953 |
| 19 | 59238368957321225 |
| 20 | 911319667593472401 |
| 21 | 14600491369553323529 |
| 22 | 243205500769215401307 |
[0,1,4,17,83,461,2873,19846,150418,1240398, 11051017,105740309,1081101474,11758967146, 135544030566,1650178088102,21155166649234, 284821038726404,4017445572746953, 59238368957321225,911319667593472401, 14600491369553323529,243205500769215401307] |