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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 85 |
| 5 | 621 |
| 6 | 5236 |
| 7 | 49680 |
| 8 | 521721 |
| 9 | 5994155 |
| 10 | 74701055 |
| 11 | 1003125282 |
| 12 | 14437634276 |
| 13 | 221727608284 |
| 14 | 3619710743580 |
| 15 | 62605324014816 |
| 16 | 1143782167355649 |
| 17 | 22014467470369143 |
| 18 | 445296254367273457 |
| 19 | 9444925598142843970 |
[1,1,3,14,85,621,5236,49680,521721,5994155, 74701055,1003125282,14437634276,221727608284, 3619710743580,62605324014816,1143782167355649, 22014467470369143,445296254367273457, 9444925598142843970] |