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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 139 |
| 5 | 1750 |
| 6 | 29388 |
| 7 | 624889 |
| 8 | 16255738 |
| 9 | 504717929 |
| 10 | 18353177160 |
| 11 | 769917601384 |
| 12 | 36803030137203 |
| 13 | 1984024379014193 |
| 14 | 119571835094300406 |
| 15 | 7995677265437541258 |
| 16 | 589356399302126773920 |
| 17 | 47609742627231823142029 |
| 18 | 4193665147256300117666879 |
[1,1,3,16,139,1750,29388,624889,16255738, 504717929,18353177160,769917601384,36803030137203, 1984024379014193,119571835094300406, 7995677265437541258,589356399302126773920, 47609742627231823142029,4193665147256300117666879] |