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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 114 |
| 5 | 1242 |
| 6 | 17129 |
| 7 | 284714 |
| 8 | 5526741 |
| 9 | 122592633 |
| 10 | 3057488913 |
| 11 | 84665033543 |
| 12 | 2576896828787 |
| 13 | 85495426794698 |
| 14 | 3070641026296061 |
| 15 | 118685141706060740 |
| 16 | 4911825483278949553 |
| 17 | 216697390123422589527 |
| 18 | 10151899714746097960699 |
| 19 | 503310218588181014061292 |
[0,1,3,15,114,1242,17129,284714,5526741,122592633, 3057488913,84665033543,2576896828787, 85495426794698,3070641026296061, 118685141706060740,4911825483278949553, 216697390123422589527,10151899714746097960699, 503310218588181014061292] |