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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 39 |
| 5 | 277 |
| 6 | 2348 |
| 7 | 23684 |
| 8 | 272955 |
| 9 | 3543901 |
| 10 | 51124052 |
| 11 | 811318628 |
| 12 | 14045786139 |
| 13 | 263429197837 |
| 14 | 5320671508868 |
| 15 | 115141595761844 |
| 16 | 2657827341263595 |
| 17 | 65185383518111581 |
| 18 | 1692767331631966292 |
| 19 | 46400793659715329348 |
| 20 | 1338843898122243225339 |
| 21 | 40562412499252848257197 |
[1,1,2,8,39,277,2348,23684,272955,3543901, 51124052,811318628,14045786139,263429197837, 5320671508868,115141595761844,2657827341263595, 65185383518111581,1692767331631966292, 46400793659715329348,1338843898122243225339, 40562412499252848257197] |