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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 28 |
| 4 | 117 |
| 5 | 472 |
| 6 | 1916 |
| 7 | 7765 |
| 8 | 31497 |
| 9 | 127707 |
| 10 | 517881 |
| 11 | 2100025 |
| 12 | 8515772 |
| 13 | 34532063 |
| 14 | 140030059 |
| 15 | 567832091 |
| 16 | 2302600696 |
| 17 | 9337214060 |
| 18 | 37863085664 |
| 19 | 153537580071 |
| 20 | 622606110920 |
| 21 | 2524713292359 |
| 22 | 10237896957896 |
| 23 | 41515420557135 |
[1,1,8,28,117,472,1916,7765,31497,127707,517881, 2100025,8515772,34532063,140030059,567832091, 2302600696,9337214060,37863085664,153537580071, 622606110920,2524713292359,10237896957896, 41515420557135] |