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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 8 |
| 3 | 88 |
| 4 | 1126 |
| 5 | 15716 |
| 6 | 232069 |
| 7 | 3564835 |
| 8 | 56382489 |
| 9 | 912031280 |
| 10 | 15018257510 |
| 11 | 250913307393 |
| 12 | 4242722219425 |
| 13 | 72470224174650 |
| 14 | 1248608968982903 |
| 15 | 21673752440979879 |
| 16 | 378677335852165297 |
| 17 | 6654158090059397480 |
| 18 | 117523324766568499072 |
| 19 | 2085095374834405245007 |
[1,1,8,88,1126,15716,232069,3564835,56382489, 912031280,15018257510,250913307393,4242722219425, 72470224174650,1248608968982903,21673752440979879, 378677335852165297,6654158090059397480, 117523324766568499072,2085095374834405245007] |