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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 47 |
| 4 | 428 |
| 5 | 4241 |
| 6 | 44407 |
| 7 | 483358 |
| 8 | 5414618 |
| 9 | 62014112 |
| 10 | 722870120 |
| 11 | 8547768832 |
| 12 | 102284029963 |
| 13 | 1236274747490 |
| 14 | 15070955944288 |
| 15 | 185089043535730 |
| 16 | 2287843817573898 |
| 17 | 28440852786725695 |
| 18 | 355345599519983962 |
| 19 | 4459821165693379625 |
| 20 | 56200963128262312342 |
[1,1,6,47,428,4241,44407,483358,5414618,62014112, 722870120,8547768832,102284029963,1236274747490, 15070955944288,185089043535730,2287843817573898, 28440852786725695,355345599519983962, 4459821165693379625,56200963128262312342] |